Occupational Ergonomics: Theory and Applications [2 ed.] 9781439819340, 9781439819357

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Occupational Ergonomics Theory and Applications Second Edition

edited by

Amit Bhattacharya James D. McGlothlin

Occupational Ergonomics Theory and Applications Second Edition

Occupational Ergonomics Theory and Applications Second Edition

edited by

Amit Bhattacharya University of Cincinnati Medical College Cincinnati, Ohio Co-Founder, OsteoDynamics, Inc. Cincinnati, Ohio

James D. McGlothlin Purdue University West Lafayette, Indiana

Boca Raton London New York

CRC Press is an imprint of the Taylor & Francis Group, an informa business

CRC Press Taylor & Francis Group 6000 Broken Sound Parkway NW, Suite 300 Boca Raton, FL 33487-2742 © 2012 by Taylor & Francis Group, LLC CRC Press is an imprint of Taylor & Francis Group, an Informa business No claim to original U.S. Government works Version Date: 20120112 International Standard Book Number-13: 978-1-4398-1935-7 (eBook - PDF) This book contains information obtained from authentic and highly regarded sources. Reasonable efforts have been made to publish reliable data and information, but the author and publisher cannot assume responsibility for the validity of all materials or the consequences of their use. The authors and publishers have attempted to trace the copyright holders of all material reproduced in this publication and apologize to copyright holders if permission to publish in this form has not been obtained. If any copyright material has not been acknowledged please write and let us know so we may rectify in any future reprint. Except as permitted under U.S. Copyright Law, no part of this book may be reprinted, reproduced, transmitted, or utilized in any form by any electronic, mechanical, or other means, now known or hereafter invented, including photocopying, microfilming, and recording, or in any information storage or retrieval system, without written permission from the publishers. For permission to photocopy or use material electronically from this work, please access www.copyright.com (http:// www.copyright.com/) or contact the Copyright Clearance Center, Inc. (CCC), 222 Rosewood Drive, Danvers, MA 01923, 978-750-8400. CCC is a not-for-profit organization that provides licenses and registration for a variety of users. For organizations that have been granted a photocopy license by the CCC, a separate system of payment has been arranged. Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identification and explanation without intent to infringe. Visit the Taylor & Francis Web site at http://www.taylorandfrancis.com and the CRC Press Web site at http://www.crcpress.com

Contents Preface, xi Editors, xiii Contributors, xv Part I Principles of Ergonomics Chapter 1   ◾   Anthropometry

3

James F. Annis and John T. McConville

Chapter 2   ◾   Skeletal Muscle Physiology and Its Application to Occupational Ergonomics

55

Robert G. Cutlip and Sharon S. Chiou

Chapter 3   ◾   Physiological Aspects of Neuromuscular Function

87

Thomas R. Waters and Amit Bhattacharya

Chapter 4   ◾   Biomechanical Aspects of Body Movement

103

Angus Bagchee and Amit Bhattacharya

Chapter 5   ◾   Biomechanical Models in Ergonomics

145

Kevin P. Granata, Kermit G. Davis, and William S. Marras

Chapter 6   ◾   Psychophysical Methodology and the Evaluation of Manual Materials Handling and Upper Extremity Intensive Work

173

Sheila Krawczyk

Chapter 7   ◾   Instrumentation for Occupational Ergonomics

205

Robert G. R adwin, Thomas Y. Yen, David J. Beebe, and John G. Webster

Chapter 8   ◾   Worker Participation: Approaches and Issues

243

Alexander L. Cohen

v

vi    ◾    Contents

Part II Application of Ergonomic Principles Chapter 9   ◾   Job Analysis

273

K atharyn A. Grant

Chapter 10   ◾   Workstation Evaluation and Design

293

David R. Clark

Chapter 11   ◾   Tool Evaluation and Design

321

Andris Freivalds

Chapter 12   ◾   Manual Materials Handling

349

Thomas R. Waters

Chapter 13   ◾   Manual Materials Assist Devices

375

Jeffrey C. Woldstad and Roderick J. Reasor (deceased)

Chapter 14   ◾   Matching the Physical Qualifications of Workers to Jobs

393

Rick Wickstrom

Chapter 15   ◾   Office Ergonomics

421

Mary O’Reilly

Chapter 16   ◾   Shift Work and Long Work Hours

451

Claire C. Caruso

Chapter 17   ◾   Design and Evaluation of a Musculoskeletal and Work History Questionnaire

477

Grace K awas Lemasters and Margaret R. Atterbury

Chapter 18   ◾   Fall Prevention in Industry Using Slip Resistance Testing

525

Mark S. Redfern and Timothy P. Rhoades

Part III Medical Surveillance for Ergonomics Programs Chapter 19   ◾   Record-Based (“Passive”) Surveillance for Cumulative Trauma Disorders

541

Shiro Tanaka

Chapter 20   ◾   Active Surveillance of Work-Related Musculoskeletal Disorders: An Essential Component in Ergonomic Programs Norka Saldaña

555

Contents    ◾    vii

Part IV Ergonomic Case Studies Chapter 21   ◾   Development and Implementation of an Ergonomics Process in the Automotive Industry: Reactive and Proactive Processes

571

Bradley S. Joseph and Glenn Jimmerson

Chapter 22   ◾   Ergonomic Control Measures in the Health Care Industry

591

Arthur R. Longmate

Chapter 23   ◾   Health Care Ergonomics

613

Thomas R. Waters

Chapter 24   ◾   Injuries and Ergonomic Applications in Construction

629

Hongwei Hsiao and Ronald L. Stanevich

Chapter 25   ◾   Ergonomic Hazards and Controls for Elevating Devices in Construction

653

Christopher S. Pan, Sharon S. Chiou, Hongwei Hsiao, and Paul Keane

Chapter 26   ◾   Ergonomics in the Agricultural Industry

695

Thomas R. Waters, Kermit G. Davis, and Susan E. Kotowski

Chapter 27   ◾   Ergonomic Analysis and Abatement Recommendations to Reduce Musculoskeletal Stress in Warehousing Operations: Case Study

721

Donald S. Bloswick and Emil Golias

Part V Physical Agents in Workplace Chapter 28   ◾   Occupational Heat Stress

737

Thomas E. Bernard

Chapter 29   ◾   Occupational Human Vibration

765

Michael J. Griffin

Chapter 30   ◾   Noise Exposure and Control

791

Sergey A. Grinshpun, Jay Kim, and William J. Murphy

Chapter 31   ◾   Nonionizing Radiation John Cardarelli II

827

viii    ◾    Contents

Part VI Current Topics Chapter 32   ◾   Cumulative Trauma Disorders of the Upper Extremities

845

Brian D. Lowe

Chapter 33   ◾   Revised NIOSH Lifting Equation

887

Thomas R. Waters

Chapter 34   ◾   Americans with Disabilities Act: Implications for the Use of Ergonomics in Rehabilitation

925

Jerry A. Olsheski and Robert E. Breslin

Chapter 35   ◾   Legal Aspects of Ergonomics

943

James J. Montgomery

Chapter 36   ◾   Real-Time Exposure Assessment and Job Analysis Techniques to Solve Hazardous Workplace Exposures

957

James D. McGlothlin and Sandra S. Cole

Chapter 37   ◾   Ergonomics and Concurrent Design

997

Peter M. Budnick, Donald S. Bloswick, and Don R. Brown

Chapter 38   ◾   Economics of Ergonomics

1013

Tapas K. R ay, Thomas R. Waters, and Steve Hudock

Chapter 39   ◾   Microergonomics: Healthy Workplace and Healthy Lifestyle in University Residence Halls

1041

Balmatee Bidassie

Chapter 40   ◾   Research to Practice in Solving Ergonomic Problems

1065

Janice Huy, Heidi Hudson, Elizabeth Dalsey, John Howard, and R. DeLon Hull

Part VII International Perspective on Ergonomics Chapter 41   ◾   Overview of Ergonomic Research and Some Practical Applications in Sweden

1089

Lennart Dimberg

Chapter 42   ◾   Current Status of the Ergonomics Research in China He Lihua, Sheng Wang, and Bingshi Wang

1107

Contents    ◾    ix

Chapter 43   ◾   Overview of Ergonomic Needs and Research in Taiwan

1119

Chi-Yuang Yu and Eric Min-yang Wang

Chapter 44   ◾   Overview of Ergonomics in Australia

1129

Jean Mangharam

Chapter 45   ◾   Ergonomics in South Korea

1173

Soo-Jin Lee, Kyung-Suk Lee, Yong-Ku Kong, Myung-Chul Jung, and Kermit G. Davis

Chapter 46   ◾   Overview of Ergonomic Needs and Research in India

1195

R abindra Nath Sen

APPENDIX A: BIOMECHANICAL MODELING OF CARPET INSTALLATION TASK, 1209 Amit Bhattacharya

APPENDIX B: ERGONOMICS CHECKLISTS, 1219 James D. McGlothlin and Amit Bhattacharya

APPENDIX C: ELECTRONIC SOURCES OF INFORMATION, 1241 James D. McGlothlin and Amit Bhattacharya

APPENDIX D: ERGONOMICS SOFTWARE SOURCES, 1245 H. Onan Demirel and Vincent Duffy

APPENDIX E: INFORMATION SOURCES FROM THE NATIONAL INSTITUTE FOR OCCUPATIONAL SAFETY AND HEALTH, 1249 James D. McGlothlin and Amit Bhattacharya

APPENDIX F: INFORMATION SOURCES FOR ERGONOMICS LITERATURE, 1261 James D. McGlothlin and Amit Bhattacharya

APPENDIX G: ERGONOMICS-RELATED PROBLEMS WITH SOLUTIONS, 1269 James D. McGlothlin and Amit Bhattacharya

APPENDIX H: AMERICANS WITH DISABILITIES ACT: REFLECTIONS 10 YEARS LATER, 1283

Preface Since the publication of the first edition in 1996, significant new advances have been made in the field of ergonomics. These advances include the impact of aging and obesity in the workplace, the role of ergonomics in promoting healthy workplaces and healthy lifestyles, the role of ergonomic science in the design of consumer products, and much more. Therefore, we saw a critical need to update the first edition, which has had more than a dozen printings and can be found in libraries all over the world. We hope you agree that the second edition fills a critical gap between existing ergonomic books by providing a comprehensive approach that encompasses the principles of ergonomics from theory to practice. It also blends medical and engineering applications to solve musculoskeletal, safety, and health problems in a variety of traditional and emerging industries ranging from the office to the operating room to operations engineering. The scope and contents of this comprehensive book are such that it is suitable for graduate (and senior-level undergraduate) students as well as a reference text for occupational safety and health professionals. This book is designed to address both the fundamentals of ergonomics (Part I) as well as practical applications (Part II) of those fundamentals in solving ergonomic problems to provide an insight into methods used to assess ergonomic risks and their control. Part III addresses the issue of connecting physical risk factors to the development of adverse health outcomes, thus providing a framework for the development of medical surveillance programs designed to monitor/control ergonomic-related challenges in the workplace. In Part IV, the reader is given the opportunity to review ergonomic case studies from a variety of industries such as health care, agriculture and construction. Part V consists of new material covering workplace-related physical agents such as workplace noise, workplace nonionizing radiation, heat, and vibration. As the field of ergonomic is growing rapidly, we have included emerging topics in Part VI, such as economics of ergonomics, application of research methods for solving “real-world” ergonomic problems, healthy workplace and lifestyle, cumulative trauma disorders (CTDs), NIOSH’s Applications Manual for the Revised NIOSH Lifting Equation, and the impact of the Americans with Disabilities Act (ADA) on ergonomics. Finally, as the field of ergonomics has had a significant impact at the international level, Part VII covers the current trends in this field from around the world. The end of the book has appendices, which include several useful ergonomic tables, list of vendors of ergonomic tools, software and video training material, ergonomic checklists, homework problems, and other background material. The benefits to the potential users xi

xii    ◾    Preface

of this book, we hope, will be numerous, including learning, understanding, and applying the fundamentals of ergonomics from theory to practice, yet appreciating the expanding applications for occupational safety and health students as well as professionals. Further, this book contains several ergonomic solutions from the very basic to systems design to prevention through design (PtD). We are very excited and proud to offer you the second edition of this book, and we are indebted to our chapter authors for their diligence in bringing you the very best the field of ergonomics has to offer. The second edition of this book could not have been possible without the many talented administrators, staff, and students who helped bring this book to fruition. In the following, we have listed some of those who helped toward this end. There may be many more whom we may have inadvertently missed. We will always be grateful for all their help. Special thanks are to Yvonne Nash for her word processing and indexing assistance; to Mike Johnson for his help in editing and indexing our many figures and photographs, and Mark Sharp for his IT support; to Dr. McGlothlin’s many students—Stephanie Snack, Maggie Cappel, Sandra Cole, and Michael White—for their organization and proofreading of the new chapters. We would also like to thank the many contributors to our appendices, including Dr. Vincent Duffy and his graduate student H. Onan Demirel. Above all, we are especially grateful for the patience and understanding of our wives, Prakriti Bhattacharya and Nancy McGlothlin.

Editors Amit Bhattacharya received his PhD in biomedical/mechanical engineering and his MS in fluid mechanics/heat transfer, from the University of Kentucky in Lexington, Kentucky, United States. He is a professor of environmental health and also a professor of biomedical engineering and mechanical engineering at the University of Cincinnati Medical College, Cincinnati, Ohio, United States. He is the founding director of the Biomechanics-Ergonomics Research Laboratories of the Department of Environmental Health. He is also the founding director of the Occupational Ergonomics/Safety graduate education program and the Pilot Research Training program sponsored by the National Institute for Occupational Safety and Health (NIOSH) and housed in the Department of Environmental Health within the College of Medicine at the University of Cincinnati. He has been teaching and conducting ergonomics/biomechanics research for more than 30 years. Dr. Bhattacharya has been active as an ergonomics/biomechanics consultant to various private industries as well as governmental agencies such as NIOSH and NIH. He serves on the editorial board of the Journal of Occupational Ergonomics and as an ad hoc reviewer for several peer-reviewed journals such as Human Factors, Clinical Biomechanics, Gait and Posture, Neurotoxicology, and the International Journal of Audiology and Environmental Health Perspectives. Dr. Bhattacharya has made significant contributions in the areas of biomechanics of slips/ falls in the workplace, heat stress, occupational biomechanics of repetitive trauma, workstation design, physiological/biomechanical effects of external vibration on animals and humans, therapeutic aspects of whole-body vibration, development of countermeasures for cardiovascular deconditioning resulting from weightlessness, and the development of noninvasive, sensitive techniques for the quantification of postural imbalance as an indicator of neurotoxicity and identification of preclinical biomechanical parameters of osteoarthritis and osteoporosis. Dr. Bhattacharya’s current research activities include (1) impact of environmental toxicants (e.g., Pb, Mn, pesticide) on the human neuromuscular system and susceptibility of developing degenerative skeletal disorder (e.g., osteoporosis); (2) design, development, and application of nano-sensors/BIOMEMS technology for early detection of neurodegenerative (e.g., Parkinson’s disease) and degenerative skeletal disorders; and (3) use of wearable and ingestible sensors for real-time assessment of heat stress among firefighters during live firefighting incidents. A recently completed NIH-supported study by his group developed a novel noninvasive tool to quantitate bone’s shock absorption (BSA) property as an aggregate response of bone’s structural integrity for early detection of fracture in osteoporosis. With support from BIOSTART organization (Ohio’s Edison incubator program xiii

xiv    ◾    Editors

for life science and health) and the University of Cincinnati, Dr. Bhattacharya cofounded a start-up company (OsteoDynamics Inc.) for commercialization of BSA system for early detection of skeletal disorders. In the “Cincinnati Innovates-2010” event, OsteoDynamics Inc. received the First Place Award for Legal and Patent Awards sponsored by Taft Law Firm of Ohio. In 2011, Dr. Bhattacharya received the finalist award from Business Courier Journal’s annual Health Care Heroes for innovation that makes an impact on health care in the Greater Cincinnati region. He is a fellow of the Biomedical Engineering Society and a charter member of the National Academy of Inventors. He is a also full member of the Human Factors and Ergonomics Society and the American Industrial Hygiene Association. James D. McGlothlin received his BA (1975) in psychology, his MPH (1977) in epidemiology, and his MS (1977) in environmental and industrial health, all from the University of Hawaii, Honolulu. He received his PhD (1988) in industrial health from the Rackham School of Graduate Studies, with a specialty in ergonomics from the University of Michigan, Ann Arbor. Dr. McGlothlin is an associate professor of health sciences in the College of Health and Human Sciences at Purdue University. His research interests include ergonomics, exposure assessment, occupational hygiene, engineering controls, and epidemiology. He is the director of the Graduate Program in Occupational and Environmental Sciences in the School of Health Sciences at Purdue University and codirector of the Center for Virtual Reality of Healthcare Center Design. He is one of the co-principle investigators for the Regenstrief Center for Healthcare Engineering (RCHE). He has served on the University Senate and on the Senate Advisory Committee to President Cordova and Provost Sands through 2011. Prior to his appointment at Purdue University (January 4, 1999), Dr. McGlothlin was a senior researcher in ergonomics and occupational hygiene engineering controls with the Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health (CDC/NIOSH). The author of more than 150 scientific, technical, and government reports, he has served as a course director in ergonomics at Northwestern University School of Engineering, Evanston, Illinois, and at the University of Cincinnati School of Medicine, Ohio. He is currently an adjunct professor in the College of Public Health at the University of Iowa, and he has courtesy appointments at Purdue’s School of Industrial Technology and Purdue Calumet. He has received several awards for his research and service to the U.S. Public Health Service, including the Surgeon General’s Exemplary Service Medal, the Outstanding Service Medal, and the Stanley J. Kessel Award for Outstanding Health Services Professional of the Year. At Purdue University, his awards include the Focus Award for outstanding contributions to the furthering of Purdue University’s commitment to disability accessibility and diversity. He is recognized as a faculty scholar for outstanding academic distinction as well as a RCHE scholar. Dr. McGlothlin became a fellow of the American Industrial Hygiene Association in March 2006. He has three patents to his credit, with one pending on wireless real-time video exposure monitoring systems. He also serves on several national and international professional committees and currently serves on the editorial boards of the Occupational and Environmental Health Journal and the Occupational Hazards Journal. Dr. McGlothlin is a certified professional ergonomist. You can find out more about him by visiting his website at www.DrMcGlothlin.com.

Contributors James F. Annis Anthropology Research Project, Inc. Yellow Springs, Ohio

Balmatee Bidassie Purdue University West Lafayette, Indiana

Margaret R. Atterbury City of Cincinnati Department of Health Millvale Health Center Cincinnati, Ohio

Donald S. Bloswick Department of Mechanical Engineering and Rocky Mountain Center for Occupational and Environmental Health University of Utah Salt Lake City, Utah

Angus Bagchee Department of Environmental Health University of Cincinnati Cincinnati, Ohio David J. Beebe Department of Biomedical Engineering University of Wisconsin-Madison Madison, Wisconsin Thomas E. Bernard College of Public Health University of South Florida Tampa, Florida Amit Bhattacharya Biomechanics-Ergonomics Research Labs Department of Environmental Health University of Cincinnati Medical College Cincinnati, Ohio

Robert E. Breslin Breslin Vocational Consultation, Ltd. Cincinnati, Ohio Don R. Brown Department of Mechanical Engineering and Rocky Mountain Center for Occupational and Environmental Health University of Utah Salt Lake City, Utah Peter M. Budnick Ergoweb, Inc. Park City, Utah John Cardarelli II U.S. Public Health Services Washington, District of Columbia

xv

xvi    ◾    Contributors

Claire C. Caruso Division of Applied Research and Technology National Institute for Occupational Safety and Health Cincinnati, Ohio

Kermit G. Davis Low Back Biomechanics and Workplace Stress Laboratory Department of Environmental Health University of Cincinnati Cincinnati, Ohio

Sharon S. Chiou Division of Safety Research National Institute for Occupational Safety and Health Centers for Disease Control and Prevention Atlanta, Georgia

H. Onan Demirel Department of Industrial Engineering Purdue University West Lafayette, Indiana

David R. Clark Industrial and Manufacturing Engineering Department GMI Engineering & Management Institute Kettering University Flint, Michigan Alexander L. Cohen Occupational Human Factors Cincinnati, Ohio Sandra S. Cole Purdue University West Lafayette, Indiana Robert G. Cutlip Health Effects Laboratory Division National Institute for Occupational Safety and Health Centers for Disease Control and Prevention Atlanta, Georgia Elizabeth Dalsey Office of Research and Technology Transfer National Institute for Occupational Safety and Health Cincinnati, Ohio

Lennart Dimberg Volvo Aero Corporation Trollhättan, Sweden Vincent Duffy Department of Industrial Engineering Purdue University West Lafayette, Indiana Andris Freivalds Department of Industrial & Manufacturing Systems Engineering The Pennsylvania State University University Park, Pennsylvania Emil Golias Occupational Safety and Health Administration Salt Lake City, Utah Kevin P. Granata Virginia Polytechnic Institute and State University Blacksburg, Virginia Katharyn A. Grant National Institute for Occupational Safety and Health Cincinnati, Ohio

Contributors    ◾    xvii

Michael J. Griffin Human Factors Research Unit Institute of Sound and Vibration Research University of Southampton Southampton, England Sergey A. Grinshpun Department of Environmental Health College of Medicine University of Cincinnati Cincinnati, Ohio John Howard National Institute for Occupational Safety and Health Washington, District of Columbia Hongwei Hsiao Division of Safety Research National Institute for Occupational Safety and Health Morgantown, West Virginia Steve Hudock Division of Applied Research and Technology National Institute for Occupational Safety and Health Centers for Disease Control and Prevention Cincinnati, Ohio

Janice Huy Office of Research and Technology Transfer National Institute for Occupational Safety and Health Cincinnati, Ohio Glenn Jimmerson Ford Motor Company Dearborn, Michigan Bradley S. Joseph Ford Motor Company Dearborn, Michigan Myung-Chul Jung Department of Industrial and Information Systems Engineering Ajou University Suwon, Korea Paul Keane Division of Safety Research National Institute for Occupational Safety and Health Morgantown, West Virginia

Heidi Hudson Division of Applied Research and Technology National Institute for Occupational Safety and Health Cincinnati, Ohio

Jay Kim School of Dynamic Systems—Mechanical Engineering College of Engineering and Applied Science University of Cincinnati Cincinnati, Ohio

R. DeLon Hull Office of Research and Technology Transfer National Institute for Occupational Safety and Health Cincinnati, Ohio

Yong-Ku Kong Department of Systems Management Engineering Sungkyunkwan University Suwon, Korea

xviii    ◾    Contributors

Susan E. Kotowski Department of Rehabilitation Sciences College of Allied Health Sciences University of Cincinnati Cincinnati, Ohio Sheila Krawczyk Liberty Mutual Research Center for Safety and Health Hopkinton, Massachusetts Kyung-Suk Lee Agricultural Safety Engineering Division National Academy of Agricultural Science Suwon, Korea Soo-Jin Lee Department of Occupational and Environmental Medicine Hanyang University Seoul, Korea Grace Kawas Lemasters Department of Environmental Health University of Cincinnati Medical School Cincinnati, Ohio He Lihua School of Public Health Peking University Beijing, People’s Republic of China

Jean Mangharam Worksafe Western Australia West Perth, Western Australia William S. Marras Biodynamics Laboratory Department of Integrated Systems Engineering Baker Systems Engineering The Ohio State University Columbus, Ohio John T. McConville Anthropology Research Project, Inc. Yellow Springs, Ohio James D. McGlothlin Purdue University West Lafayette, Indiana James J. Montgomery Montgomery, Rennie & Jonson Cincinnati, Ohio William J. Murphy Center for Health-Related Aerosol Studies University of Cincinnati Cincinnati, Ohio Jerry A. Olsheski School of Applied Behavioral Sciences Ohio University Athens, Ohio

Arthur R. Longmate Johnson & Johnson New Brunswick, New Jersey

Mary O’Reilly School of Public Health State University of New York New York, New York

Brian D. Lowe Division of Applied Research and Technology National Institute for Occupational Safety and Health Cincinnati, Ohio

Christopher S. Pan Division of Safety Research National Institute for Occupational Safety and Health Morgantown, West Virginia

Contributors    ◾    xix

Robert G. Radwin Department of Biomedical Engineering University of Wisconsin-Madison Madison, Wisconsin Tapas K. Ray Department of Health and Human Services National Institute for Occupational Safety and Health Centers for Disease Control and Prevention Cincinnati, Ohio Roderick J. Reasor (deceased) Virginia Polytechnic and State University Blacksburg, Virginia Mark S. Redfern Department of Otolaryngology and Departments of Industrial Engineering University of Pittsburgh Pittsburgh, Pennsylvania Timothy P. Rhoades Applied Safety and Ergonomics, Inc. Ann Arbor, Michigan Norka Saldaña Johnson & Johnson Shared Services Caguas, Puerto Rico Rabindra Nath Sen Ergonomics Laboratory Department of Physiology University of Calcutta Calcutta, India Ronald L. Stanevich Division of Safety Research National Institute for Occupational Safety and Health Morgantown, West Virginia

Shiro Tanaka Division of Surveillance National Institute for Occupational Safety and Health Cincinnati, Ohio

Bingshi Wang Ethicon Endo-Surgery, Inc. Cincinnati, Ohio

Eric Min-yang Wang Department of Industrial Engineering National Tsing-Hua University Taiwan, Republic of China

Sheng Wang School of Public Health Peking University Beijing, People’s Republic of China

Thomas R. Waters Applied Psychology and Ergonomics Branch National Institute for Occupational Safety and Health Cincinnati, Ohio

John G. Webster Department of Biomedical Engineering University of Wisconsin-Madison Madison, Wisconsin

Michael White Purdue University West Lafayette, Indiana

xx    ◾    Contributors

Rick Wickstrom WorkAbility Wellness Center WorkAbility Systems, Inc. West Chester, Ohio

Thomas Y. Yen Department of Biomedical Engineering University of Wisconsin-Madison Madison, Wisconsin

Jeffrey C. Woldstad University of Nebraska-Lincoln Lincoln, Nebraska

Chi-Yuang Yu Department of Industrial Engineering National Tsing-Hua University Taiwan, Republic of China

I Principles of Ergonomics

1

Chapter

1

Anthropometry James F. Annis and John T. McConville CONTENTS 1.1 Introduction 1.2 Background and Significance to Occupational Ergonomics 1.3 Relevant Concepts and Terminology 1.3.1 Anatomic Concepts 1.3.2 Types of Measurements 1.3.2.1 Static Measurements 1.3.2.2 Dynamic Measurements 1.3.3 Equipment 1.3.3.1 Traditional Static Measurements 1.3.3.2 Looking Ahead 1.3.4 Statistical Considerations 1.3.5 Sources of Data 1.3.5.1 Civilian Data 1.3.5.2 Military Data 1.3.5.3 Future Needs 1.3.6 Applications for Anthropometry 1.4 Anthropometric Criteria for Ergonomic Application 1.4.1 General Body Size Variability 1.4.2 Sexual Variation 1.4.3 Age Variation 1.4.4 Racial/Ethnic Variation 1.4.5 Specialized Data 1.4.5.1 Clothed Anthropometry 1.4.5.2 Working Postures 1.4.5.3 Reach 1.4.5.4 Linkage and Computer Models 1.4.6 Anthropometry and Seated Work 1.4.7 General Guidelines 1.A Appendix: Ergonomic Tables and Figures References

4 4 5 5 7 8 8 9 9 10 11 14 15 16 17 18 19 19 19 20 21 21 22 23 23 26 26 29 30 52 3

4    ◾    Occupational Ergonomics: Theory and Applications

1.1 INTRODUCTION Anthropometry involves the systematic measurement of the physical properties of the human body, primarily dimensional descriptors of body size and shape. Anthropologists have been measuring humans for hundreds of years, but for only the last 50 years or so have the dimensions been used in an organized fashion to improve the design and sizing of the things we use in everyday life. Often the problem with the application of anthropometry to a design problem will be the lack of certain necessary measurements or the need to accommodate a wide range in size and shape variability into a single, often inflexible design. Applied anthropometry—that is, the use of anthropometric data in the design and construction of a wide variety of items from clothing to spacecraft—is a relatively new discipline whose practitioners are still learning to cope with the exponential character of technology and its impact on the kinds of information needed to describe the physical and biological characteristics of our species. It grew out of physical anthropology, which traditionally studied body size and function with the goal of resolving our ancestry and identifying the existing varieties of Homo sapiens. Today, we are still trying to learn what to measure to satisfy an even younger discipline called ergonomics. The original impetus for the development of applied anthropometries, and perhaps ultimately ergonomics, was the need to improve the effectiveness and efficiency of equipment used in combat during World War II. The military tie was so strong in the United States that it has been recognized only relatively recently that civilian industry could also benefit from the proper use of anthropometry in the design of products and workstations. Today industry has embraced the concept so eagerly that the word ergonomics, which derives from the Greek ergon (work) and nomos (natural laws of), has become popularly used in advertisements. A concern for ergonomics currently spawns industrial action committees, comprising members of both management and labor, whose purpose is to improve the human–machine interface to achieve a healthier, safer, and more efficient workforce. Anthropometric data are a necessary and basic tool for attaining this end as well as improving the design of a wide variety of products.

1.2 BACKGROUND AND SIGNIFICANCE TO OCCUPATIONAL ERGONOMICS There appears to be two major divisions of ergonomics. The first deals with the worker, the machine the worker uses, and the environment in which the worker operates. The objective of this branch of ergonomics is to create the best possible situation on the job relative to the welfare of the worker’s physical and mental health, the efficiency of production, and the quality of the product produced. Second, there are the characteristics of the manufactured product(s) that interact with the human user. In reviewing the literature we have found no less than 20 different definitions of ergonomics. One of the most inclusive examples is as follows: The ability to apply information regarding human character, capacities, and limitations to the design of human tasks, machines, machine systems, living spaces, and environment so that people can live, work, and play safely, comfortably, and efficiently.

Anthropometry    ◾    5  

All of the definitions of ergonomics mention work or the workplace, but, more important from our perspective, they also mention the human operator in the equation. The ways in which work is related to the individual vary greatly throughout industry, yet it is very difficult to think of any work situation in which the application of anthropometry or anthropometric principles could not make the work environment healthier, safer, and more efficient. At the same time, ergonomists and designers are not trying to make their products either cheaper or more expensive but rather better suited to the limitations of the human user. Anthropometry cannot be separated from these ergonomic processes, because they cannot be carried out without the knowledge of human dimensionalities. The relationship of anthropometry to occupational ergonomics is both straightforward and complex. All the tools used in manufacturing, all the workspaces in which the manufacturing is done, and virtually all of the items produced by the manufacturing process interact with the human body or human body space. In the most automated of manufacturing environments, humans must still make and repair the machines and robots, and the products that come off the assembly line must be designed for human users. Software is still written by humans and entered onto the computer disk or tape through a keyboard operated by the human hand. It is hard to think of an exception. Ultimately there is a human in the loop; hence, human dimensions are likely to be needed for some time to come. Obviously, physical anthropologists are prepared to include almost any measurement that describes the shape, size, or function of the body or its parts as components that make up the area of anthropometry. The data discussed most frequently in this chapter are those used as dimensional descriptors of general body size, those used for specific types of working postures, and those describing reach capabilities. Data for related areas of investigation, such as mass distribution and segmental moments of inertia, range of joint motion (ROJM), strength, and biomechanical aspects of the human body, are discussed elsewhere in this book. In one way or another all of these data are at some point in the design process useful to the occupational ergonomist.

1.3  RELEVANT CONCEPTS AND TERMINOLOGY 1.3.1  Anatomic Concepts In performing anthropometric measurements, some knowledge of human anatomy is essential, because almost all measurements are defined in terms of some body part or some specific location on a specified part. Subjects being measured are directed to assume specific predefined positions. The standard reference point is the anatomical position, in which the person stands erect with arms at the sides and the palms of the hands facing forward. From this posture the descriptive terms that define the body’s principal axes and the resultant planes are derived. From these planes, too, the basic terms used to describe the relative position or location of relevant points on the body structure are developed. The most commonly used terms are shown diagrammatically in Figure 1.1. Typically, the principal axes, X, (front-to-back), Y (side-to-side), and Z (head-to-foot), divide the body into three planes: sagittal, which divides the body into right and left parts (XZ); coronal, which divides the body front to back (YZ); and transverse, which divides the body cross-sectionally (XY).

6    ◾    Occupational Ergonomics: Theory and Applications Lateral

Medial Lateral

Posterior YZ

XZ

Anterior

Proximal

Tra nsv pla erse ne

Superior

Distal

XY

e

lan

S

lp tta agi

Inferior Co r pla onal ne

FIGURE 1.1  Terminology used to define position and location on the body.

The relative positions of particular structures or features in or on the body are defined as follows: Anterior/posterior: Structures nearer the front or ventral side are anterior (+X) to those located nearer to the back or dorsal surface, which are posterior (−X). Medial/lateral: Structures located nearer to the center of the body or to the midsagittal plane relative to others are medial to those located away from the central body on the left (+Y) or right (−Y) side, which are lateral. Superior/inferior: Structures located nearer the head are located superior (+Z) to those below, which are termed inferior (−Z). For example, the heart is located superior to the kidneys. Proximal/distal: On the limbs, parts that are near the trunk are proximal whereas those farther from the body central are distal. A finger is distal to the elbow.

Anthropometry    ◾    7  

9

19

1. 2. 1 3. 4. 3 5. 5 6. 7 7. 8. 11 9. 10. 13 11. 15 12. 17 13. 14. 21 15. 16. 17. 18. 19. 20. 23 21. 22. 23. 24. 25. 25

Sellion Glabella Zygion Tragion Menton Infraorbitale Gonion Suprasternale Cervicale Acromion Ziphoid Radiale Tenth rib Stylion Iliocristale Dactylion Anterior superior iliac spine Lateral femoral epicondyle Posterior superior iliac spine Fibulare Trochanterion Tibiale Suprapatella Medial malleolus Lateral malleolus

4

2

6

8

10

12

14

16 18 20 22

24

FIGURE 1.2  Selected skeletal landmarks used to define traditional anthropometric measurements.

Frequently the points between which a given dimension is measured are actually drawn on the subject’s skin by the anthropometrist. Such points are called landmarks. Some landmarks are simply determined by a certain feature found in the topography of the body surface, for example, the tip of a finger; others must be palpated and marked in relation to skeletal architecture. Twenty-four of the twenty-five landmarks shown in Figure 1.2 are of the latter variety. In a recent survey of U.S. Army personnel (ANSUR) [1], nearly 100 landmarks were used to define the basic group of 132 dimensions measured. Approximately 70 of the landmarks were actually drawn on the subjects’ skin by landmarking specialists (e.g., landmarks shown on Figure 1.2), and another 30 landmarks were located by observation by the measurer, for example, distal tip of thumb, inferior tip of earlobe. 1.3.2  Types of Measurements Most commonly, anthropometry refers to traditional dimensional descriptors of body size. Except for weight, these measurements basically provide the straight-line or curvilinear distance between two points obtained under static prescribed conditions. Basic categories of static anthropometric dimensions include lengths, depths, breadths, and distances that are basic descriptors of body size. Surface contour measurements, such as arcs and circumferences, are more complex because they contain elements of three-dimensional (3D) shape in one plane. In most major surveys, the use of other types of anthropometric measurements is limited. Simple forms of reach, for example, functional leg length, overhead reach, grip reach, and thumb tip reach, may be measured.

8    ◾    Occupational Ergonomics: Theory and Applications

1.3.2.1  Static Measurements Traditional static dimensions may be briefly described as follows:

Height: Typically the distance along the Z axis from the floor or seated surface to a specific point on the body. Length: Usually used to name the distance between two landmarks that are found on a single segmental part of the body. In some cases the term distance is used. Some lengths or distances describe the entire segment, whereas others describe a portion of a segment along the longitudinal axis of the part. Some lengths are contours or complex distances measured on the body surface, for example, sleeve length. Distances between linkage centers used in computer models and drafting board manikins are called link lengths. Depth: The distance between two landmarks found on the anterior and posterior surfaces of the body along the X axis. Breadth: The distance between two points found on the right and left (lateral) sides of the body. Arc: Curvilinear or surface contour distance between two points on the body, often on the head or face. Circumference: Closed curvilinear contour that provides the distance completely around the body part. In most cases the circumference is located perpendicular to the longitudinal axis of the body part. Reach: Specialized arm–hand distance in a particular posture or condition. In most cases, dimension names include the previous designations, but in some cases no such descriptive label is used, for example, span, stature, or scye. The idea of the defining labels used to describe a particular type or class of measurements begs the question of standardization of measurement definitions, a matter over which anthropologists have often been unable to agree. One text that deals with standards was published in 1988 [2]. This book concentrates on nutritional/health assessment measurements, but a number of applied dimensions are discussed. At a conference of practicing anthropologists held at Wright–Patterson Air Force Base in the late 1960s, agreement on a list of 29 dimensions fundamental to applied users was barely achieved [3]. It would be helpful to the user if dimensions with the same name were always measured in the same way. This is very often not the case. Dimensions with the same name from any two surveys may have well been measured differently; hence, the difference observed between the two values may in part be due to procedures used and not to population or sampling differences. 1.3.2.2  Dynamic Measurements Dynamic measurements such as isometric strength and ROJM have traditionally been measured in separate surveys. The measurement of ROJM is probably the simplest of such measurements in anthropometries. Traditionally, planar ROJM measurements are made using a goniometer, which in its simplest form is nothing more than a 180° or 360° protractor with extended arms, one of which is movable to track the segment. A related

Anthropometry    ◾    9  

measurement of this type is the reach envelope, which at some point in the measuring process always involves movement of the arm-shoulder complex and sometimes movement of the trunk or torso. In most cases, however, these measurements are obtained statically, that is, they are expressed as the change or difference in location across the movement, that is, begin-end delta. Too few truly dynamic anthropometric measurements are made on humans, and most of those that may be thought to qualify as dynamic contain static elements. For example, isotonic strength testing in which muscle lengths change may be said to be dynamic. Recently, isokinetic devices, in which the speed of the movement produced is controlled, have been developed for this type of testing. Strength and biomechanics are discussed elsewhere in this book. 1.3.3  Equipment 1.3.3.1  Traditional Static Measurements The basic tools of the anthropometrist are the anthropometer, a variety of calipers, and a tape measure. The most commonly used instruments are shown in Figure 1.3. Typically, anthropometers are precision instruments made up of four interconnecting sections of tubular metal that are engraved in millimeter (mm) intervals. Current models are square in cross-section and are capable of measuring stature or other heights from the floor and seated surfaces as well as straight lengths and distances up to 210 cm when completely assembled. The heights (starting with 0 mm from the floor or seated surface) are read using a movable slide housing that contains an adjustable perpendicular blade, which is placed in alignment with, or lightly on, the desired measuring point. The slide housing contains a window with centerline that enables the user to read the distance to the nearest 0.5 mm on the engraved scale. Typically, only the nearest whole millimeter is recorded. The upper two sections of the anthropometer may be used as a beam caliper, as they are equipped with a millimeter scale on the side opposite the main scale that starts with 1 2 3

4

Beam Spreading

Sliding Anthropometer Calipers

FIGURE 1.3  Basic equipment used to perform traditional anthropometric measurements.

10    ◾    Occupational Ergonomics: Theory and Applications

0 mm at the top fixture (see Figure 1.3). The beam caliper, which is capable of measuring distances of up to 95.0 cm, is used for measuring whole body depths and breadths as well as many straight linear distances between landmarked points. Anthropometers may be purchased individually or as part of a set that includes a sliding and a spreading caliper and a tape measure.* These tools have made up the professional anthropometrist’s basic measuring kit over a long time period; however, they are slowly being displaced by more modern automated systems. A wide variety of special application calipers and other instruments are also available for anthropometric measuring, although most of these will not be needed by the industrial ergonomist. Other, less complex items requiring a minimum of equipment or shop skills may be homemade. Of the latter, the most frequently used are special tables for seated measurements with adjustable buttock plates and foot rests. Many of the seated workspace dimensions are obtained using such tables. Static measuring of various regions of the body such as the head, hands, or feet frequently requires the use of stabilizing or referencing surfaces to help control the repeatability of the measurement. A foot box is often used, for example, in measuring various foot lengths and breadths. To obtain head and face dimensions referenced to fixed surfaces, a device called a headboard has been used in a number of military surveys [4,5]. A subject places the top (vertex) and back (occiput) of the head firmly against the two perpendicular surfaces, and the anthropometrist measures the distance from the two reference surfaces to defined landmark locations using a depth/height gauge. An automated form of this device was developed for use in the 1988 survey of U.S. Army personnel [6,7]. The automated headboard provided 3D coordinates for 26 selected landmark locations on over 8000 soldiers. An industrial ergonomist may find it necessary to perform measurements of employees on the job. In this case an effort should be made to incorporate defined and reproducible controls into the measuring methods. A number of simple devices can be designed and built by users to improve reliability and accuracy or to provide special dimensional values to suit a specific need. If the anthropometrist wishes to compare any data collected to those existing in some database, however, care should be exercised to duplicate the original procedure. In some cases this caveat should extend to the equipment used. The final report that describes the methods and summary statistics for the ANSUR survey [1] contains a description of a number of devices used for special application measurements as well as the procedures used to measure over 132 body dimensions. The ANSUR database represents the largest, most recent, and most comprehensive anthropometric survey of Americans in existence. Thus, we recommend that the reader follow the procedures developed for this survey until comparable data are available on civilians (see Section 1.3.5). 1.3.3.2  Looking Ahead To date, most anthropometric data have been obtained using manually operated instruments or devices such as those discussed earlier. Usually these measurements are performed one at a time and recorded by hand. These data provide a two-dimensional (2D) description of the body worthy of an earlier time. But biologists have for centuries wanted * The best anthropometer currently on the market is the GPM, manufactured in Switzerland and imported into this country by Seritex, Inc., 450 Barell Avenue, Carlstadt, NJ 07072. A catalog is available.

Anthropometry    ◾    11  

to be able to quantitatively describe the 3D form of the human body. Early in this century, researchers began exploring techniques to obtain large quantities of digital information about the body surface size and structure through the use of stereophotogrammetric cameras [8]. A slow and tedious digitization process was required to obtain the 3D data from the resulting photographs. Today, the use of lasers, video, cameras, and other devices in combination with graphics software makes it possible to rapidly collect large quantities of high-density digital information on limited areas of the body. In the near future, it will likely be possible to scan the entire body and generate 3D coordinates on up to 500,000 points on the body surface in just a few seconds. Before the use of true 3D shape becomes routine, work remains to be done on methods used to summarize the massive quantity of 3D coordinates and improve the ability of optoelectronic devices to resolve the many cracks and crevasses on the surface of the body. This is one of the reasons that traditional anthropometry will continue to be needed for some time to come. With the onset of the ability to collect high-density digital information in three dimensions, we now can talk about body shape in quantitative ways, for both surface contours and internal organs. Scientists and physicians can now examine 3D full-color images of a person’s internal structures using a variety of computerized scanning techniques. It will be some time before people outside the medical field will know exactly how to use it on the job, but currently such information is invaluable in the early detection or confirmation of cumulative trauma disorders and other afflictions that result from poor ergonomics in the workplace. When high-density 3D coordinate data for the whole body surface become state-of-the-art, simple point-to-point measurement may be viewed as rudimentary. More important, the engineer, the ergonomist, and the designer will have at their fingertips any human dimension they may need to resolve a given design problem. 1.3.4  Statistical Considerations Fortunately, values for most traditional static anthropometric dimensions are normally distributed. This characteristic permits the use of a number of simplifications that the reader may find helpful. The classic shape of the normal distribution curve is shown in Figure 1.4 in conjunction with increments of standard deviation (SD) relative to the mean (x–). The mean ±1 SD can quickly be seen to include 68% of the population sampled, while the mean ±2 SD and the mean ±3 SD include the variability exhibited by approximately 95% and 99.8%, respectively, of the population. The relationships between the mean ± increments of the SD and selected percentile levels are given in Table 1.1. As can be seen, the ubiquitous 5th to 95th percentile range is approximately equivalent to the mean ±1.65 SD. Two fundamental questions to be resolved in the application of anthropometric data to design are (1) what database should be selected? and (2) what statistical value(s) should be used? The theoretical answer to the first question is simple: The database of choice is the most recent survey containing the desired dimensions obtained on a large sample of the target user population. In practical fact, this desirable database usually does not exist. Hence, the database will probably have to be selected from the most appropriate of those available. The choice of a statistical approach depends on the problem to be solved. If the design requires only a single dimension, the designer could attempt to accommodate the entire

12    ◾    Occupational Ergonomics: Theory and Applications

–3 SD

–2 SD

50%

–1 SD

16%

34%

2.5% .1%

Mean

47.5% 49.9%

+1 SD

50%

34%

+2 SD

+3 SD

16% 47.5%

2.5% 49.9%

.1%

FIGURE 1.4  The normal distribution curve and relative proportions of the population represented

by multiples of the standard deviation.

TABLE 1.1  Using the Mean and Standard Deviation to Estimate Percentile Values for Normally Distributed Data Percentile Value 99.5 99 97.5 97 95 90 80 75 70 50 30 25 20 10 5 3 2.5 1 0.5

Formula Mean + (2.58 × SD) Mean + (2.32 × SD) Mean + (1.95 × SD) Mean + (1.88 × SD) Mean + (1.65 × SD) Mean + (1.28 × SD) Mean + (0.84 × SD) Mean + (0.67 × SD) Mean + (0.52 × SD) Mean Mean − (0.52 × SD) Mean − (0.67 × SD) Mean − (0.84 × SD) Mean − (1.28 × SD) Mean − (1.65 × SD) Mean − (1.88 × SD) Mean − (1.95 × SD) Mean − (2.32 × SD) Mean − (2.58 × SD)

range of variability in the user population for that variable. Such simple design problems are in reality rare. Usually, a number of body dimensions are required, and it is here that the difficulty begins. Probably the most common error in thinking about the use of anthropometry in sizing and design is that if an individual is small (or large) for a given dimension, then that person

Anthropometry    ◾    13  

is small (or large) for all other dimensions. This is seldom, if ever, true—a fact that can be demonstrated in at least two ways. One common misconception is that the mean, which lies near the center of the most densely populated portion of the distribution, is the best value to use to satisfy size requirements of the largest number of people. This is true only if the problem is univariate and if the design will include no adjustability. The “average person” has long been dear to designers’ hearts, but, as has been demonstrated by Daniels [9], this individual probably does not exist. In 1952, Daniels analyzed a sample of 4063 U.S. Air Force flyers to determine how many men with average stature (mean ± 0.3 SD) would also be of average size for a successively inputted series of clothing design dimensions for which the same criterion for average was used. A total of 1055 men met the average criterion for stature, but not a single individual was found who also had average values for all 10 clothing dimensions. We recently conducted a similar analysis on male and female subsamples taken from the ANSUR survey [10]. To reduce overall variability, samples of 2074 white males and 1438 white females were used in the analysis. The results of the analysis are shown in Table 1.2. As can be seen in Table 1.2, no men remained in the sample after screening for eight dimensions, and only one woman of the 309 with average stature was average for all 10 dimensions measured. The rate of dropout would vary with a different list of dimensions, of course, but in all cases a very small group of individuals would remain after a few rounds of screening. As can be seen from Table 1.2, for example, only 5%–6% of the original subjects remained after only the second round of selection. The “average person” is a statistical concept; such a person does not in fact exist. A second misconception involves use of percentile values in designs. Probably the most frequently specified design limits are the 5th and 95th percentiles. These percentiles are TABLE 1.2  The “Average”a Man and Woman (Values in mm) Men Dimension Stature Chest circumference Sleeve length Crotch height Vert. trunk circ. Hip circumference Neck circumference Waist circumference Thigh circumference Crotch length

Women

Mean ± 0.3 SD

n

Percent

Mean ± 0.3 SD

nb

Percentc

1745–1784 978–1018 876–898 823–849 1624–1668 968–1004 374–385 849–899 580–608 632–656

486 115 60 28 18 10 3 1 0 0

23.4 5.5 2.9 1.4 0.9 0.5 12 and ≤30 lifts per hour for activities lasting ≥2 hours per day. Yet another criticism by DOT users is that the range for levels of occasional force for heavy and very heavy strength levels is too high based on consideration of materials handling loads that represent a risk for injury according to ergonomic risk assessment models [18–20]. The practical usefulness of the very heavy strength level is also questionable because so few jobs even exist that require a very heavy level of strength.

398    ◾    Occupational Ergonomics: Theory and Applications

In a recent normative study of functional capacities for workers employed at different strength levels [21], the data for workers performing heavy and very heavy physical demands had to be combined into one category because only a small number of subjects in the sample were employed at these levels. In this study, no female subjects in the normative sample were even working at the heavy or very heavy physical demands categories. Ergonomic risk assessment tools such as the ACHIG TLVs and the Washington’s hazard zone checklist identify upper limits for infrequent lifting of 70 lb due to safety risk [19,20]. For a lower lift strength task, this is reasonably consistent with epidemiologic studies that demonstrate an increased odds ratio for lower back injury at two times the recommended weight limit (RWL) using the NIOSH lifting equation [22]. These ergonomic risk assessment models would support recommendations by DOT users to lower the upper limit of the “heavy” strength for occasional lifting from 100 to 70 lb. Finally, many DOT users and the OIDAP commission have advocated for revision of strength level definitions to limit this factor only to materials handling characteristics and categorize postural demands such as standing and sitting as separate physical demand factors. Examples of revised “strength” scale definitions proposed by the Occupational Health Special Interest Group of the American Physical Therapy Association are: Very light: 1–10 lb maximum and a negligible amount of weight frequently Light: 11–25 lb maximum, up to 10 lb frequently, or a negligible amount of weight constantly Medium: 26–40 lb maximum, 11–25 lb frequently, or up to 10 lb of weight constantly Heavy: 41–70 lb maximum, 26–40 lb frequently, or up to 15–25 lb of weight constantly Exceptional: >70 lb maximum, >40 lb frequently, or >25 lb of weight constantly When placing a worker in a specific job, one must know the zone for lifting in addition to frequency and weight of the load handled. A worker may be unable to lift 10 lb overhead due to a shoulder injury yet still be well matched for a job that requires lifting up to 50 lb at waist level or below. A worker with a back or shoulder injury can often be accommodated by being placed in a job where heavier items are lifted between waist and chest level. The Applications Manual for the Revised NIOSH Lifting Equation [18,22] may be used to characterize and evaluate lifting tasks based on the maximum and average force exerted, the location of the hands and angle of asymmetry at the origin and destination of the lift, the frequency and duration of lifting, and coupling to the object. This revised NIOSH lifting equation may be used to justify ergonomic redesign or to validate the design of a job-specific work fitness test. Commercially available systems for functional capacity evaluation (FCE) use different methods to determine the end point for tests of worker abilities during manual materials handling tasks. The Liberty Mutual normative studies used a psychophysical method whereby the opinion of the subject being evaluated determines the testing end point by self-monitoring feelings of exertion or fatigue and adjusting the weight accordingly. With kinesiophysical methods, the evaluator relies on functional movement criteria to

Matching the Physical Qualifications of Workers to Jobs    ◾    399  

determine the end point of testing, with the examiner using observational skills to more objectively determine when the subject is struggling with the load as the end points. The kinesiophysical method has some distinct advantages compared to psychophysical testing for subjects that have a poor perception of their own ability, have psychological factors such as fear avoidance behavior, or are suspected of not providing accurate reports or not demonstrating a full effort. Using this method, an examiner’s systematic observational rating of effort was shown to be the single best indicator of sincere effort by Jay et al. [23]. Another investigation by Reneman [24] showed that effort level can be determined with validity on materials handling tasks by visual observation. Variations in box dimensions, coupling, lifting zones, and repetitions between systems account for different results when comparing the results of tasks administered by different FCE systems. For example, Ijmker et al. [25] explored the concurrent validity of test results of upper lifting tasks of the Ergo-Kit FCE and the Isernhagen work systems (IWS) FCE and concluded that upper lifting tasks of the Ergo-Kit FCE and the IWS FCE do not meet the criteria for concurrent validity and can, therefore, not be used interchangeably. In this investigation, it was not a surprising conclusion that the mean maximum lifting capacity was substantially higher for the Ergo-Kit method because the two kinesiophysical methods were quite different in the zone of lift (Ergo-Kit upper lift to chest level versus Isernhagen lift to overhead level) and in the number of repetitions required (Ergo-Kit upper lift strength test is a one-repetition task versus Isernhagen waist-to-overhead lift (WOL) task that requires achievement of five repetitions at each load progression). The Isernhagen WOL task requires multiple repetitions in a more physically challenging lifting zone. Differences between FCE methods are further illustrated in the concurrent validity study by Rustenburg et al. [26] that demonstrated significantly higher mean maximum lifting capacity for the Ergo-Kit lower and upper lifting tasks compared to the ERGOS work simulator. This conclusion was also not surprising, given the differences in these FCE systems in end point methodology (ERGOS is a psychophysical method, whereas Ergo-Kit is a kinesiophysical method) and repetitions required (ERGOS work simulator requires three repetitions, whereas Ergo-Kit requires only one repetition). In this investigation, the zones of lifting were more similar, but a higher frequency of repetitions and psychophysical method used with ERGOS work simulator method was more likely to result in fatigue and a lower acceptable weight for the subjects, compared to the Ergo-Kit method. These studies suggest that use of multiple repetitions to determine an end point may represent a frequent test rather than an occasional test of materials handling capacities. This speaks to the need for a common taxonomy to provide a better framework of referencing tests of workers’ manual materials handling abilities. Physical demand factors 2–20 in the DOT represent work tolerances that are classified according to a frequency scale [9,10] based on percentage of an 8 h work shift: Constantly (C): Activity or condition exists for 2/3 or more of the time. Frequently (F): Activity or condition exists from 1/3 to 2/3 of the time. Occasionally (O): Activity or condition exists up to 1/3 of the time. Not present (N): Activity or condition does not exist.

400    ◾    Occupational Ergonomics: Theory and Applications

The OIDAP Physical Demands Subcommittee reported that “most agree that some sort of classification system of the extent of repetition as well as duration should be included…It may be that the number of repetitions would vary depending on whether one is classifying upper extremity vs. trunk repetition… The length of time a physical demand is performed and the length of a workday should be captured in the data gathering process.” DOT users have recommended further delineation of the frequency scale to specify repetition ranges and to add one or two new levels of frequency that correspond to “rarely” (corresponding to 1%–5% of an 8 h shift) and “exceptional” (corresponding to >8 h of exposure during a work shift). The “exceptional” category would apply to standing tolerance of workers such as nurses in a hospital setting that commonly work 12 h shifts or to sitting tolerance of over-the-road truck drivers that drive for 11 or more hours during a given shift. This is important because jobs that require constant driving in a constrained sitting posture for extended periods of time are much harder for workers with health conditions that limit sitting tolerance that jobs that involve constant sitting in an office setting where the worker has more flexibility to change work postures. DOT users have advocated for separation of postural factors such as standing and sitting from the existing DOT strength factor definition to better assess the impact of these work tolerance factors. The DOT taxonomy contains five physical worker–job match factors under aptitudes that are rated using an aptitude or skill-level scale: Extremely high: The top 10% of the population High: The highest third exclusive of the top 10% of the population Medium: The middle third of the population Low: The lowest third exclusive of the bottom 10% of the population Very low: The lowest 10% of the population Some adjustment in these aptitude definitions may be warranted to better distinguish between people and jobs that have varying abilities. The practical usefulness of the “extremely high” aptitude levels for the physical aptitude factors is low for disability adjudication purposes, given that only a small percentage of jobs existed in 1991 (0.0%–0.4%) that required this level of aptitude or skill for the five physical aptitudes. For example, adding a “none” category may help better distinguish jobs that have no requirement for a given aptitude factor. The Revised Handbook for Analyzing Jobs includes many examples of functional anchors that provide examples of task performance that correspond to specific aptitude levels. The Occupational Health Special Interest Group of the American Physical Therapy Association recommended that a number of physical demand factors evaluated by health care professionals would be better rated by the degree of aptitude or skill required than by a frequency scale that is more oriented toward tolerance during the work shift. Examples of specific factors recommended for rating as an aptitude include ambulation agility, ambulation stamina, climbing, near vision acuity, far vision acuity, hearing acuity, and keyboarding speed.

Matching the Physical Qualifications of Workers to Jobs    ◾    401  

The world of work has changed considerably since the last update of the DOT database in 1991. Changes to manufacturing, distribution, and service processes have further lowered the physical demands of many jobs. It is anticipated that ongoing efforts of the OIDAP will result in an improved occupational information system that results in further refinement of rating scales, as well as addition or modification of specific factors to improve person-side measurements based on well-defined functional levels. Commercial FCE systems must evolve with improvements in worker–job match taxonomies and evidence-based practice research.

14.4  EVOLUTION OF THE WORKABILITY EJOBMATCH TAXONOMY In this section, operational definitions and related examples of worker assessment methods are described for the physical ability taxonomy developed for the WorkAbility eJobMatch System to illustrate a new direction for future worker–job match taxonomy. 14.4.1  Materials Handling Abilities WorkAbility eJobMatch includes the following materials handling ability factors: 1. High lift strength (>52 in.) is the maximum load that is raised or lowered using one or both hands while reaching from shoulder level to overhead. This relates to Physical demand factor 1 (strength) as defined by the U.S. Department of Labor [9]. A dynamic high lift strength task is commonly administered during many FCEs. For most healthy subjects, shoulder strength is often the limiting factor. The WorkAbility high lift strength test is depicted in Figure 14.1. This method involves raising the bottom of the tote pan to a vertical mark that corresponds to 12 in. above shoulder level. Use of inexpensive painter’s tape to mark the desired vertical end point for the bottom of the tote

FIGURE 14.1  WorkAbility high lift strength test.

402    ◾    Occupational Ergonomics: Theory and Applications

FIGURE 14.2  WorkAbility chest lift strength test.

pan eliminates the need for fixed or adjustable height shelving that cannot be readily transported within a clinic or to other locations. Setting the destination limit at 12 in. above shoulder level is consistent with upper reach limit recommended for lifting in the ACGIH publication of TLVs, which also references the High lift zone as 52–72 in. [19]. 2. Chest lift strength (30–52 in.) is the maximum load that is raised or lowered using one or both hands while reaching from waist to below shoulder level. This relates to physical demand factor 1 (strength) as defined by the U.S. Department of Labor [9]. A dynamic lift strength task at this mid-range zone is commonly administered during many FCEs and often called a knuckle-to-shoulder lift. For most healthy subjects, elbow and grip strength is the limiting factor, because the subject can usually protect the shoulders by positioning the upper arms close to the body. The WorkAbility chest lift strength test is depicted in Figure 14.2 [13]. This method involves lifting a tote pan to a vertical mark that positions the bottom of the tote and hands at a vertical height of 52 in. The 52 in. height was selected because it marks the upper range of a reference task used by Snook [16,17] to communicate the maximum acceptable loads for workers performing twohanded symmetrical lifting. The 52 in. height is related to the upper vertical limit for the chest zone in the ACGIH TLV publication [19]. The WorkAbility chest lift strength is quite similar to the Ergo-Kit upper lift strength test [27,28], except for protocol modification to foster complete mobility and addition of examiner ratings of effort that are similar to the research on the EPIC lift capacity method by Jay et al. [23] 3. Carry strength (28 ft or less) is the maximum load that is transported by walking, usually by holding the load in one or both arms. This relates to physical demand factor 1 (strength) as defined by the U.S. Department of Labor [9]. The limiting factor during carry is usually arm strength. A dynamic carry strength task for short distances is common to many FCEs. The WorkAbility two-arm carry strength test is depicted in Figure 14.3. This method involves carrying a tote pan with progressive weights for a distance of 28 ft. This distance was selected because it was one of the reference

Matching the Physical Qualifications of Workers to Jobs    ◾    403  

FIGURE 14.3  WorkAbility two-arm carry strength test.

distances used for carry tasks in the normative studies by Liberty Mutual [16–17] to investigate the maximum acceptable loads for workers performing two-handed symmetrical carry tasks. Two-handed carrying tasks that occur over long distances are not routinely assessed in most FCE systems, because it is usually possible to reduce these physical demands by using a cart or to use another device such as a back pack to transport the load. Keeping the two-handed carry distance short for a job task also limits the risk of tripping because carrying an object in both arms tends to obstruct the subject’s view of the ground and impose greater agility challenges. If the subject has a unilateral problem affecting only one arm, then a comparative assessment may be warranted to evaluate right versus left carrying strength. 4. Knee lift strength (15–30 in.) is the maximum load that is raised or lowered using one or both hands while reaching between knee and waist level. This zone of lifting is tested less often in other FCEs; however, this zone is important to because it usually represents the strongest lifting zone because the subject can use the strongest muscle groups in more optimal positioning of joints to the greatest biomechanical advantage. The WorkAbility knee lift strength test is depicted in Figure 14.4. This method involves lowering and raising a tote pan from table level to and from a vertical mark that puts the hands at 18 in. This knee lift strength definition is reasonably comparable to the ACGIH zone from 12 to 30 in. that is referenced in the TLV. 5. Low Lift strength (30 times per hour) is the average of loads lifted or carried more frequently than 30 repetitions during a given hour. It is usually determined on the job by sampling the heaviest 31 loads for each hour during a representative 8 h work shift. Constant lifting is often not practical to evaluate during a job-specific or comprehensive FCE. It is usually best to monitor an injured worker’s psychophysical ratings and physiological parameters while the worker is participating in a progressive transitional work program at the jobsite or in a clinic-based work rehabilitation program. 14.4.2  Work Tolerances WorkAbility eJobMatch includes the following work tolerances factors: 1. Sit or stand work option is performing work that can be done with a choice of either sitting or standing. 2. Standing only is remaining on one’s feet in an upright position at a workstation or when moving about. This relates to physical demand factor 1 (strength) as defined by the U.S. Department of Labor [9]. This may be measured in terms of frequency (percent of the day) and maximum and average time spent standing for any given function. 3. Sitting only is remaining in a seated position. Includes driving done while sitting. This relates to physical demand factor 1 (strength) as defined by the U.S. Department of Labor [9]. This may be measured in terms of frequency (percent of the day) and maximum and average time spent sitting for any given function. 4. Operating foot controls is performing work activities that operation of controls with one or both feet. This relates to physical demand factor 1 (strength) as defined by the U.S. Department of Labor [9]. This may be measured in terms of frequency (percent of the day), type of foot movement or coordination required, and maximum and average duration and speed of foot use. It is important to note whether the dominant foot, other foot, both feet, and either foot may be used for the task. Foot use ability is usually estimated from performance on other tests. 5. One-handed work option is performing work that can be done with a choice of using either hand. One-handed work options may be evaluated by individual assessment of the right versus left arms during tests of finger dexterity, manual dexterity, lifting, and carrying. One of the greatest shortcomings of the existing DOT is its database limitations prevent assessment of opportunities for workers that have substantial physical limitations involving only one upper extremity. 6. High reaching above shoulder is extending either arm to reach from shoulder level to overhead. This relates to physical demand factor 8 (reaching) as defined by the U.S. Department of Labor [9] that is based on the percentage of time a worker is extending hand(s) and arm(s) in any direction. DOT users have advocated for more specific classification of reaching in vertical zones, because of confusion created by this operational definition. Reaching above shoulder level may be further delineated on a

408    ◾    Occupational Ergonomics: Theory and Applications

FIGURE 14.9  Total-Body Dexterity Tester Overhead Manipulation Test.

functional job analysis by maximum and average duration for reaching with the arms in the upper range. It is important to note whether the dominant arm, other arm, both arms, or either arm may be used for reaching overhead. Reaching above shoulder level may be evaluated by tolerance in performing a work sample such as the Total-Body Dexterity Tester [31,32] Overhead Manipulation Test that is shown in Figure 14.9.

7. Head turning >45° is rotating the head 45° or more either way with respect to the upper torso. This may be evaluated by measuring cervical rotation with a goniometer and observing the behavior of subjects when distracted and performing a work sample such as the Total-Body Dexterity Tester [31,32] as depicted in Figures 14.9 through 14.12.

8. Forward bending/stooping is bending downward more than 20° at the waist or hips while standing. This relates to physical demand factor 4 (stooping) as defined by the U.S. Department of Labor [9]. This may be measured in terms of frequency (percent of the day) and maximum and average duration of stooping. When stooping is required occasionally, this can be measured with the Total-Body Dexterity Tester during the Forward Manipulation Test [31,32] as shown in Figures 14.11 and 14.12. This ability can also be inferred from other physical ability tests such as the Ergo-Totes

Matching the Physical Qualifications of Workers to Jobs    ◾    409  

FIGURE 14.10  Total-Body Dexterity Tester.

FIGURE 14.11  Total-Body Dexterity Tester Forward Manipulation Test.

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FIGURE 14.12  Total-Body Dexterity Tester Lower Manipulation Test.

Low Lift Strength Test (Figure 14.5) or Ergo-Totes Knee Lift Strength Test (Figure 14.4) as previously shown. When stooping is required frequently, fitness for stooping may be measured with the WorkAbility knee lift frequent test. 9. Low work (e.g., kneel/crouch) is bending at the trunk and knees to work with the hands below knee level in a kneeling, squatting, or seated posture. This relates to physical demand factor 5 (kneeling) and physical demand factor 6 (crouching) as defined by the U.S. Department of Labor [9]. This may be measured in terms of frequency (percent of the day) and maximum and average duration of working at a low level. In many instances, it is up to the worker to decide what method of working to employ at a lower level, e.g., whether to kneel, crouch, or stoop. When low work is required, the Total-Body Dexterity Tester Lower Manipulation Test [31,32] may be administered in the subject’s preferred work posture (Figure 14.12). 14.4.3  Physical Aptitudes 1. Ambulation agility is the ability to quickly move about for short periods of time while walking, jogging, or running. This relates to physical demand factor 3 (balancing), which is defined by the U.S. Department of Labor [9] using a frequency scale based on the percentage of time a worker is maintaining equilibrium when standing in place or moving on varying surfaces. Ambulation agility would be better conceptualized as a skill-based rating that spans the continuum from walking very slowly with use of an assistive device to sprinting and cutting on an athletic field, based on functionally described rating examples:

a. None: Ambulation not required, all job duties can be done from a wheelchair



b. Very low: Walking only short distances at a very slow pace (e.g., 25°) Borg CR-10 scale Deferred to professional Rating of peak force judgment exertion (visual analog scale from 0 to 10)

Repetitive Motion Rating of “speed of work” based on how fast the worker is working relative to percentage of MTM-1 standard time

Visual analog scale rating of HAL with verbal descriptors of activity level, or, identifying hand force duty cycle and rest periods and referring to table in ACGIH documentation Wrist angle used in equation to Percentage of endurance Assumes 10,000 hand scale grip force capacity for capacity calculated as a motions can be types of grip/pinch function of the time performed in one day. Elbow flexion/extension–3 posture is held, rest The number of categories (>10° flex, 10° period, total working allowable hand flex–30° ext, >30° ext); shoulder time, and load motions are reduced flexion–4 categories (0°–20°, (estimated as %MVC) by other multipliers 20°–45°, 45°–90°, >90°); reflecting forcefulness shoulder abduction–4 categories and posture (0°–30°, 30°–60°, 60°–90°, >90°) Wrist radial/ulnar deviation–2 The effort required to Assumes 30 technical categories; wrist flexion/ carry out a series of actions per minutes extension–2 categories (0°–45°, technical actions as are allowable. >45°); forearm pronation/ expressed as a Allowable technical supination–2 categories; percentage of MVC actions are reduced shoulder elevation–3 categories based on multipliers (0°–20°, 20°–60°, >60°) for posture and force

derived from MTM (methods-time measurement) predetermined motion time systems and can involve significant subjective judgment on the part of the analyst. Moore and Garg [58] recommend that video recordings of the job be observed as the basis for the analysis. The American Council of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value for Hand Activity Level (HAL TLV) is a voluntary standard established for the determination of safe levels of upper limb activity in work performed for greater than 4 h per day  [59]. Similar to the strain index, the HAL TLV is appropriate for “mono-task” work, characterized by a predictable cyclic pattern of work elements and jobs that do not have variable task exposure. The HAL TLV does not account for posture of the upper limb, which is deferred to the professional judgment of the job analyst. Application of the HAL TLV involves determination of two parameters: the peak hand force and the hand activity level (HAL).

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Peak hand force can be derived by a number of methods. If continuous time measurements of force are obtained, the 90th percentile level for hand/finger force is used—the rationale being that the finger transmits force between the work object and the tendons and muscles in the hand, wrist, and forearm [60]. In the absence of direct measurement, the peak force can be estimated by the analyst, or estimated by the worker. Psychophysical approaches such as the Borg CR-10 scale [61], visual analog scale percentage of maximal exertion, and force matching have been applied to obtain worker estimates of hand force level. Using the forcematching approach, the worker is asked to estimate and reproduce the force exertion on a hand dynamometer in a similar configuration as the work situation dictates. The reliability of the estimates are improved when arm/wrist/hand postures and grip contact conditions more closely approximate those of the actual task [62]. It is recommended that individual worker estimates of peak force be normalized to the strength capability of the worker population for the job. The second parameter, the HAL, reflects the repetitive nature of the work in the exertion of force. HAL can be derived quantitatively from the observed exertion frequency and exertion recovery time using a look up table (see Table 32.4). The HAL can also be rated by the job analyst using a 10-point Visual Analog Scale with verbal anchors describing the frequency of hand motions and/or repeated exertions of hand force [63]. This is a less quantitative but more rapid approach as the analyst makes a judgment about the motions and repeated forceful task elements of the hand(s). The HAL and peak force are plotted on a graph and can be interpreted in relation to the threshold limit value (TLV) and a more conservative action level (AL) indicating the need to initiate some form of intervention. In the example described in Section 32.4 and illustrated in Figure 32.7 (bottom panel), the solid line represents the TLV, and the dashed line, the action limit. The Occupational Repetitive Actions (OCRA) method [64,65] is based on a count of “technical actions”—a term used to describe micro-motion elements in the task that would be considered in a methods-time measurement analysis. Colombini [64] cited this approach as an advantage of the method asserting that it is easy to define and recognize technical actions and that company technicians, who are experienced in production organization, can relate to this construct. Technical actions can be described in terms of their frequency of occurrence, and the OCRA frequency constant for allowable technical TABLE 32.4  Hand Activity Levels for Combinations of Exertion Frequency and Duty Cycle Frequency Exertions/s 0.125 0.25 0.5 1.0 2.0

Duty Cycle % 0–20

20–40

40–60

60–80

80–100

1 2 3 4 —

1 2 4 5 5

— 3 5 5 6

— — 5 6 7

— — 6 7 8

Source: From American Conference of Governmental Industrial Hygienists (ACGIH), Documentation of the TLVs and BEIs (6th edn.), Cincinnati, OH: ACGIH Worldwide, 2005.

Cumulative Trauma Disorders of the Upper Extremities    ◾    863  

actions is 30 per min. The allowable number of technical actions is reduced by multipliers that account for force exertion, posture, recovery periods, and additional factors including exposure to vibration and/or cold, localized compression of soft tissues, requirements for accuracy, use of gloves, and hand impact. The formulation of the multipliers and how they reduce the allowable frequency of technical actions is similar to that of the original and revised NIOSH Lifting Equation [66,67]. The OCRA posture multiplier reduces the allowable technical actions based on theoretical assumptions about duration severity, which embodies both the duration of the awkward posture and its degree of deviation from neutral. Severity scores for the posture multiplier are proportional to the perceived discomfort elicited by the degree of postural deviation. Scaling of posture magnitude is based on 50% of the range of motion of the joints as shown in Table 32.3. The force multiplier decreases the frequency constant in proportion to the equivalent rating of perceived effort for the work cycle. Perceived effort is derived from the Borg CR-10 scale for perceived exertion. A disadvantage of the OCRA method is that it can be time-consuming for complex tasks and multi-task jobs. Analyses almost always require observation of a video recording of the job and use of pause and single frame advance capabilities. A simplified OCRA checklist has subsequently been developed which reduces the complexity of the method. The CTD risk index [68] has been less widely adopted, but is another detailed approach to assessing a job for increased risk for CTDs of the upper extremity. This method is based on established relationships between grip and pinch force capacity and wrist posture and discounting the allowable force exertion based on exertion duration and recovery periods. The method is somewhat similar to OCRA in that it involves counting the number of hand grip or pinch motions in a work cycle and converting this to a daily total based on the work cycle time and work duration. The daily count of grip motions is normalized to 10,000 per day, which is assumed to be the daily allowable limit. (The 10,000 daily hand motions compares favorably with 30 technical actions/minute, the frequency constant of the OCRA method.) The CTD risk index also adjusts the power and pinch grip force to the observed grip span based on equations expressing MVC capability as a function of grip span. The consideration given to posture in this method is complex and entails the use of equations for endurance capacity based on static hold time as a function of wrist posture, a recovery period between successive awkward postures, a point assignment for the severity of the postural magnitude (see Table 32.3), and the percentage MVC supported in relation to the 51 pound load constant of the NIOSH lifting guideline [66]. A simpler version of the CTD risk index appears in Niebel and Freivalds [69] which reduces the analysis complexity and time and is more appropriate for the evaluation of a larger number of jobs. This version calculates an index based on a hand motion frequency factor (relative to the allowable limit of 10,000 daily hand motions), a posture factor, a force factor, and miscellaneous factors such as use of gloves, presence of sharp edges on work contact surfaces, vibration exposure, and cold temperature. 32.6.2.2  Whole-Body Methods Including the Upper Extremity In addition to the upper extremity–specific job analysis tools listed in the Section 32.6.2.1, other methods have been developed that assess ergonomic risk factors to all musculoskeletal regions.

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These methods are classified here as whole-body methods. Ovako Working posture Analysis System (OWAS) and Rapid Upper Limb Assessment (RULA) were two of the earlier methods to be developed, and subsequent methods are similar in their approach. OWAS [70] emphasizes gross posture of the body and, in terms of the upper limbs, contains only a broad classification of shoulder posture based on the elevation of the elbows. The distal upper limb joints (elbows and wrists) are not considered in the OWAS method. The OWAS approach to the accumulation of points in proportion to the severity of individual body segment postures and the load handled has been adopted by other methods. RULA is classified by many, including the original authors, as an upper limb assessment method [71]. It is grouped in this review with the whole-body methods because it includes assessment of lower extremity posture—unlike the methods discussed earlier that are specific to the upper extremity. RULA is largely based on an analysis of working posture. Severity points are accumulated for postures that deviate from neutral. There are four nonneutral posture categories for shoulder flexion/extension: >20° extension, 20° extension–45° flexion, 45°–90° flexion, >90° flexion, with one point added for abduction of the upper arm. There are two non-neutral categories for elbow flexion (0°–60°, >100°) and two non-neutral categories of wrist flexion/extension (beyond neutral to 15° flex/ext, >15° flex or ext) with one point added for a “deviated or twisted” wrist. Posture severity is classified according to the posture held for the longest duration or for which the highest loading occurs. Force exertion and repetition are established by classifying resistance or load handled according to levels of less than 2 kg, 2–10 kg, or greater than 10 kg and whether the load is static, intermittent, or repeated. The RULA grand score is derived from an accumulation of points for the severity of upper limb stresses in combination with the severity of neck, trunk, and leg stresses. The Rapid Entire Body Assessment (REBA) [72] is a variation of RULA developed for application in the health care industry. REBA adds load coupling in a manner similar to the revised NIOSH Lifting Equation [66]. REBA is largely postural based, and the scoring is similar to that of RULA in the translation of the score to a risk or action level. Loading on the Upper Body Assessment (LUBA) [73] differs from the previously described approaches in the rationale for assigning severity to postural deviation. LUBA posture severity scaling was based on a psychophysical study of perceived postural discomfort [74] and matching the ratio of severity scores to the ratio of discomfort levels associated with various postures. The LUBA method considers only posture, and its application considers only the psychophysical perception of postural discomfort as the determinant of acceptable working postures. PATH [75,76] differs from the methods discussed earlier in that it is a work samplingbased approach that was developed more specifically for construction work, in which the postures, motions, and forces exerted are variable and non-cyclic in nature. Assessments using PATH consider postures (P), activities (A), tools (T), and handling (H) inherent in a number of construction trades. Because construction work is typically characterized by variable, non-cyclic patterns of exposure, jobs cannot be analyzed at the unit of a short duration fundamental work cycle. PATH relies on fixed-interval observations in real-time. PATH emphasizes trunk and leg posture in the framework of the OWAS method, but does

Cumulative Trauma Disorders of the Upper Extremities    ◾    865  

include shoulder posture stresses when work is performed with elbows above shoulder height. Because the validity of work sampling increases when a large number of observations are included, the authors recommend that PATH observations be made in intervals less than 60 s. 32.6.2.3  Validity Considerations Several studies have examined upper extremity observational-based job analysis methods for their predictive and/or external validity, which describe how well they predict the prevalence of upper extremity MSDs. Knox and Moore [77] assessed 28 jobs in a turkey processing plant with classifications of “hazardous” or “safe” based on a strain index score of 5 as a cutoff. Presence of MSD outcomes, or morbidity classification, was based on a physician review of OSHA 200 injury logs. Sensitivity, a measure of the percentage of jobs that are correctly predicted as being associated with morbidity, was reported as 0.91; specificity, a measure of the percentage of jobs correctly predicted as being associated with no morbidity, was reported as 0.83. An odds ratio of 50.0 was reported. Rucker and Moore [78] reported even stronger predictive validity of the strain index when applied in two manufacturing facilities. In a larger cross-sectional study of 352 workers across three manufacturing facilities, Latko et al. [63] reported modest odds ratios for hand outcomes when considering only the ACGIH HAL rating as an exposure metric. Collapsing the continuous HAL scale into three categories (low, medium, high) resulted in odds ratios up to 3.33 (1.27–8.26, 95% CI) for the low vs. high category comparison in predicting tendinitis. The jobs evaluated in this study exhibited little variability in exposure level for hand posture or force exertion. Thus, the contribution of these stressors in predicting hand outcomes could not be determined. Franzblau et al. [79] conducted an even larger cross-sectional study with over 900 workers at 7 facilities to assess the predictive validity of the ACGIH TLV. TLV categories were positively associated with elbow/forearm tendonitis and CTS; however, sensitivity and specificity were shown to be modest for most outcomes, with the former being less than 0.6 for all outcomes. The authors noted a high prevalence of reported symptoms in jobs below the TLV action limit. In a recent study of 567 workers, Spielholz et al. [80] evaluated the predictive validity of both the strain index and ACGIH TLV. The risk factors that were related to disorders of the dominant distal upper extremities were peak and most common hand force, a strain index greater than 7.0 vs. less than 3.0 (odds ratio = 2.33), and strain index greater than 7.0 vs. less than 7.0. For the nondominant hand, the HAL category less than 4.0 vs. HAL category greater than 4.0 (OR = 2.81) was the only significant relationship with health outcomes. The Spielholz et al. [80] study suggests that a strain index of 7 achieves roughly equivalent sensitivity and specificity in predicting MSD outcomes and was associated with significant odds ratios for distal upper extremity outcomes in the dominant hand. This finding is in line with the recommendations of Rucker and Moore [78] that the criterion value of 5.0 might be increased—perhaps to as high as 9.0, for manufacturing jobs. Spileholz et al. [80] reported some differences between the strain index and ACGIH TLV in terms of risk category classification (safe, action level, and hazardous zones). With a strain index of 7.0 as the hazard

866    ◾    Occupational Ergonomics: Theory and Applications

zone threshold, and 3.0 as the safe zone threshold, the strain index classified more jobs in the hazard zone than the ACGIH TLV, and that the TLV categorized more jobs as safe. This group [81] has suggested that the strain index may be more protective, particularly for jobs in the median exposure levels, and that when combining data from multiple studies, agreement in risk classification between the two methods was 75%. The studies of Bao et al. [81] and Armstrong et al. [60] suggest that the HAL TLV action limit could be lowered. In addition to their external validity, that is, how well they are predictive of disease or morbidity, a consideration in the application of observational-based methods is their internal validity. Internal validity refers to how well the methods represent the exposure variable(s) they are intended to quantify. Methods for characterizing exposure based on visual observation and estimation of risk factors should be interpreted with an appreciation for the limitations in the ability of observers to make accurate estimates of the risk factor levels. This has been illustrated most clearly for the visual estimation of working posture. In general, the posture category boundaries of job analysis methods have not been selected based on empirical studies of what job analysts can reliably detect by visual observation. Studies of the accuracy of posture estimation from video recording suggest that postural misclassification errors are inversely proportional to the size of the joint segments of interest [74,82]. When considering the width of angular posture categories (in degrees), a trade-off exists between the probability of error occurrence and the magnitude of the error when one is made [82,83]. van Wyk et al. [83] recently illustrated this concept empirically by deriving posture categories that optimize the probability of occurrence of misclassification errors and the magnitude of the errors as a function of the posture category width. The example shown in Figure 32.6 represents elbow flexion/extension and indicates an optimal category width of 25–30 degrees. Since elbow flexion/extension has approximately 120 degrees in the functional range of motion, van Wyk et al. [83] suggest that a four category scale in 30° increments is optimal in consideration of the accuracy of observer judgment. Table 32.5 shows the posture categories that optimize visual

15 # of errors

70

# of errors Degrees error

60 50 40

10

30 20

5

Degrees error

20

10 0

10

20 30 40 Category width (degrees)

60

0

FIGURE 32.6  Optimized posture category size for elbow/flexion extension showing the trade-off

between the probability of posture misclassification (number of errors made) and the misclassification error magnitude (in degrees). (Reproduced from van Wyk, P.M. et al., Ergonomics, 52, 921, 2009. With permission.)

Cumulative Trauma Disorders of the Upper Extremities    ◾    867   TABLE 32.5  Optimal Posture Category Widths (in Degrees) and Number of Categories for Trunk, Shoulder, and Elbow Postures

Category width Optimal number of categories

Trunk Flexion

Trunk Lateral Bend

Shoulder Flexion

Shoulder Ab-/Adduction

Elbow Flexion

30° 4

15° 3

30° 5

30° 5

30° 4

Source: From van Wyk, P.M. et al., Ergonomics, 52, 921, 2009.

judgment of posture based on the van Wyk et al. [83] study. While this represents only a single study and did not include wrist postures, these findings are in line with those of Bao et al. [81] who concluded that interrater reliability was superior with 30° posture category widths versus a smaller width, and that for most postures, 30° angle intervals appear to be appropriate. It should be noted that for radial/ulnar deviation of the wrist, an interval of 30° from neutral represents most, if not all, of the effective range of motion. Thus, wrist radial/ulnar deviation presents a dilemma in designing posture scales with categories that are small enough to capture differences in biomechanical risk, yet large enough that the angular intervals can be visually discriminated by observers conducting the posture analysis. Because of the relatively small size of the body segments, and smaller range of movement, visual discrimination of wrist radial/ulnar deviation is problematic for observational posture assessment [82,84]. 32.6.2.4  Example of Observational-Based Exposure Assessment An example of the application of the HAL TLV is as follows. A job on an automotive radiator assembly production line was video recorded, and the hand force profile for the dominant (right) hand was determined using two approaches. The first approach was with a wearable glove with thin profile force sensors attached to the palm surface to measure hand contact force with the dominant hand. Figure 32.7 (top panel) shows a force profile for a typical work cycle with a cycle time of 15 s. The second approach was using the Multimedia Video Task Analysis, or MVTA, system (see Section 32.6.4) and manually marking video frames at the transition points between hand force and no hand force exertion. Using MVTA, five periods of hand force exertion were identified for the right hand (see Figure 32.7, middle panel). These correspond closely to five distinct exertions of force evident from the directreading measurement (top panel). The total time duration of the force exertions sums to 7.6 s, resulting in a duty cycle of 50%. A 15 s work cycle with five exertions yields a force frequency of 0.33 exertions per second. Using Table 32.4, the HAL rating was obtained for this combination of exertion frequency and hand force duty cycle, and was determined to be greater than 3 and less than 4. Thus, a range of 3–4 was used. The normalized peak hand force in the grip of the radiator when lifting it from the pallet was estimated to be between 40% and 50% of MVC. By plotting the HAL and normalized peak force as shown in Figure 32.7 (bottom panel), it can be determined that the job falls above the action limit (dashed line) but below the TLV and can be characterized as a job in which some form of intervention should be considered.

868    ◾    Occupational Ergonomics: Theory and Applications

Retrieve radiator transfer

Force

Insert fastner with electric driver

Set in fixture

Coupler 1 attachment

Coupler 2 attachment

Work cycle

Work cycle

Normalized peak force

10 8 6 4 2 0

0

2

6

4

8

10

HAL

FIGURE 32.7  Example of HAL calculation (top and middle panels) and interpretation (bottom

panel). The top panel shows a continuous recording of hand force and the middle panel an observational analysis of exertion duty cycle using the MVTA™ software.

32.6.3 Continuous-Recording Instrumentation-Based Methods Though not the most widely adopted, it is generally believed that the most valid approach to quantifying physical risk factors for upper limb CTDs is by direct measurement with continuous-recording instrumentation [47,56]. UECTD risk factors have been quantified with a variety of continuous-recording measurement instrumentation, most notably those for measuring muscle electrical activity (electromyography), external muscle force (load cell/strain gauge transducers, thin profile pressure and force sensors), joint motion, or kinematics (electrogoniometry), limb segment orientation (inclinometry), and vibration (accelerometry). Motion capture systems, which are based on optical and magnetic

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technologies, have been used in studies conducted in more controlled environments, but are generally impractical in industrial settings. The following is a brief overview of continuous-recording instrumentation applicable in the assessment of UECTD risk factors. 32.6.3.1  Force Exertion The surface electromyogram (SEMG) is a recording of the electrical activity in underlying skeletal muscle detected by electrodes attached to the skin surface over the belly of the muscle. SEMG recordings are typically subjected to data reduction and analysis of amplitude as a correlate of force exertion or amplitude and/or frequency spectra as indicators of muscle fatigue [85,86]. The amplitude of the detected electromyogram (EMG) signal is referenced (or normalized) to a known level of muscle contraction in a standardized exertion, and subsequent amplitudes can be expressed as percentages of the reference exertion force output. The reference exertion can be elicited as the maximum force the worker can exert (the maximum voluntary contraction, or MVC) or a submaximal exertion level that is controlled by standardizing a static load on the muscle. As an example, power grip force on a grip dynamometer can be calibrated (or normalized) to the SEMG amplitude of extrinsic muscles in the forearm that create forceful flexion of the fingers in the grip [87]. This SEMG to force relationship can be used to convert the SEMG measured in a gripping task to an equivalent dynamometer grip force level, provided that grip span and wrist posture are equivalent. Normalized SEMG has also been interpreted with respect to the duration of intensity levels and their frequency of occurrence as a percentage of working time. This approach has been labeled exposure variation analysis [86,88] and has been applied to examine activity in non-cyclic work where force exertions vary and lack fundamental work cycles [89]. A simpler approach is to express the SEMG activity in terms of its amplitude probability distribution function (APDF), where the cumulative frequency or probability of occurrence is plotted against exertion level [90]. Some investigators have adopted or developed specialized systems for the continuous time measurement of external force exertion by the hand, which are particularly applicable to the grip force on tool handles. Two examples of such systems require either fabrication of special handles with embedded force transducers [91] or the application of thin flexible pressure sensors between the surface of the handle and the hand [92–94]. As an example of the former, Liberty Mutual has developed a Hand Tool Force Measurement System [91] based on an instrumented handle core with embedded strain gauges. The system has been used to measure multi-axis compression forces in the grip of the handle and moments at the cutting blade of a knife used in a variety of poultry processing jobs (see Figure 32.8a). As an example of the latter, Kong and Lowe [94] instrumented a wearable glove with thin profile force sensors on the phalangeal segments and metacarpal heads of the palm surface to measure finger segment contact force in the power grip of tool handles (see Figure 32.8b). A wearable force sensor system has the advantage of versatility, in that measurement of hand contact force is not limited to the particular tool that is instrumented. This contrasts with the embedded strain gauge approach where sophisticated fabrication of a single tool

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(a)

(b)

FIGURE 32.8  (a) Knife handle instrumented for grip forces in three axes and moments with force

transducers embedded in the cylindrical core. (Photo courtesy of R. McGorry, Liberty Mutual Research Institute for Safety.) (b) Wearable (glove-attached) thin profile resistive sensors for measurement of contact force on the phalangeal segments and metacarpal heads.

handle can be costly and time-consuming. However, a disadvantage of the wearable thin profile sensor approach is that the measurement depends on the completeness of sensor coverage on the palm surface in contact with the object in the grip. The wearable glove approach is also intrusive, as the measurement device itself may alter the subject’s interaction with the handle. Force transducers embedded in a tool handle accurately resolve the resultant forces on the handle unintrusively and are independent of the distribution of contact surface on the handle. 32.6.3.2  Posture and Motion The most commonly reported instrumentation-based measurements of posture and motion of the hand, wrist, and forearm have been acquired using electrogoniometry. An electrogoniometer is a device that measures joint displacement using a transducer that spans the joint of interest. Wrist electrogoniometers commonly have an endblock attached on the metacarpal bones of the hand and on the forearm proximal to the wrist. The flexion/extension and radial/ulnar deviations of the wrist can be detected by these transducers (refer to Figure 32.4). Rotation of the forearm (supination/pronation) requires a torsional sensor in which twist between the device endblocks are calibrated to a degree of axial rotation. An applied example of the use of electrogoniometry to quantify wrist and forearm motions is the study of Albers and Hudock [95]. This study evaluated risk factors associated with hand rebar tying with a traditional method using manual pliers and with a handheld battery-powered automated tying device. Electrogoniometry was used to quantify the reduction in wrist/forearm motions associated with the automated device relative to the hand-tying method. Ironworkers tied rebar intersection points at ground level in the grid of rebar that provided reinforcement to a poured concrete bridge surface (see Figure 32.9). The rebar segments intersected at 7 in. intervals, and 75% of the total intersection points required tying. Electrogoniometric recordings were made for approximately 30 min for each of three tying devices: the conventional manual method with pliers, an automated battery powered tying device, and the battery-powered device with an extension handle

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Pliers

Battery powered

Battery powered + extension

Velocity (deg/s)

160 120 80 40 0

Flexion/extension

Radial/ulnar Pronation/supination

FIGURE 32.9  Example of electrogoniometry used to measure mean (+s.d.) wrist motion velocities

for three methods of rebar tying: manual pliers tying, battery-powered tying, and battery-powered tying with the addition of an extension handle. The bar graph shows the substantial reduction in wrist motion velocities, particularly for flexion/extension and pronation/supination, with the battery-powered tying device. (From Albers, J.T. and Hudock, S.D., Int. J. Occup. Saf. Ergon., 13, 279, 2007. With permission; photos by Earl Dotter.)

designed to reduce or eliminate trunk bending (see Figure 32.9). This was an ideal application for wrist electogoniometry since the traditional approach of hand tying rebar with pliers is associated with many repetitive high-velocity wrist and forearm motions that could not be reliably estimated by visual judgment. Albers and Hudock [95] reported that wrist motion velocities in the flexion/extension, radial/ulnar deviation, and forearm rotation (supination/ pronation) axes were reduced by 76%, 30%, and 63% respectively by adoption of the automatic rebar tying device. (Figure 32.9). Inclinometry is a method for dynamically assessing the orientation of a limb segment with respect to gravity. One example is when the inclinometer is attached to the upper arm segment, the device can be calibrated to arm orientation and used to evaluate upper arm elevation [76]. 32.6.3.3  Direct-Reading Exposure Assessment Methods (DREAM) While direct-reading instrumentation is believed to be the most objective and quantitative method for assessing risk factor exposure, its use in occupational ergonomics appears to be highly concentrated in research applications. In a survey of Certified Professional

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Ergonomist (CPE) practitioners, Dempsey et al. [96] found that 31% of CPEs reported having ever used EMG and, of these, only 2% rated EMG as “easy to use.” Conversely, 52% of practitioners reported having used RULA, and 20% of these rated RULA as easy to use. A similarly low rating for easy to use was reported for electrogoniometry, which only 18.5% of CPEs reported as having ever used. A trend within these data appears to be that directreading measurement techniques are not viewed as favorably, or are not as widely adopted, by practitioners for assessing risk factor exposure in ergonomic analyses. Advances in sensor technologies and portable direct-reading instruments for other physical agents such as noise, radiation, aerosols, and dust have led to an initiative in 2008 by NIOSH in the area of Direct-Reading Methods [97]. Under this initiative, the vision for directreading methods (DRMs) in occupational exposure assessment is based on a self-contained instrument, wearable by the worker that can “…provide on-site measurement of exposures in units (such as parts per million parts of air, or ppm) that indicate whether or not the exposures pose an occupational health or safety risk and if the prevention methods employed are actually providing the proper level of protection” [97]. This definition is clearly inspired by the monitoring of air-borne chemical agents and the sampling of hazards to which workers are exposed through respiratory or dermal pathways. Nonetheless, this initiative may benefit the area of MSD prevention and CTD risk assessment if novel and improved technologies for measuring the risk factors of force, posture, repetitive motion, and vibration result. NIOSH and the American Industrial Hygiene Association sponsored a workshop in 2008 to address research needs related to DRMs for occupational exposures to hazards related to noise, radiation, aerosols, surface sampling and biomonitoring, gases and vapors, and ergonomics. The workshop titled “Direct-Reading Exposure Assessment Methods” (D.R.E.A.M.) served to solicit stakeholder input for the purpose of developing a research agenda for DRMs for exposure assessment. The ergonomics and vibration breakout session of the workshop focused on DRMs for the hazard of physical loading on the musculoskeletal system and the assessment of exposure to biomechanical risk factors for WMSDs. Discussion centered on the importance of immediate interpretation of exposure data, that is, to provide a real-time indication of exposure level. Real-time acquisition of data in the workplace (on-site) is necessary. However, the group was somewhat divided on the need for real-time interpretation of the data. Some participants felt that there was a need for DRMs to acquire the exposure data and interpret the measured exposure level in realtime. An example of such a scenario is when immediate feedback to the worker is desirable for changing work habits or technique, or as a form of biofeedback. Other participants believed that the real-time interpretation of exposure is not a necessary characteristic for a DRM and that post-processing of the data may be necessary for reconstruction and interpretation of exposure level. It was generally agreed that reducing data post-processing time is desirable. The discussion also emphasized the need to improve the usability, portability, and ruggedness of existing technologies or in the development of new technologies. 32.6.4 Computer Video–Based Task Analysis and Video Exposure Monitoring Observational-based ergonomic assessments have traditionally been conducted by pencil and paper documentation of risk factors observed with the aid of analog video

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playback equipment. Some approaches to posture analysis have integrated computerized exposure documentation with observation from analog video tape recording [98]; however, prior to the digital video camcorder, these methods were less common. Advances in digital video recording technology have greatly simplified the integration of video playback and computer-assisted exposure assessment and time study. Digital video and computer-based time study and task analysis systems are now commonly used to aid the process of ergonomic job analysis. Commercial systems are available that provide a user interface to control the playback of digital video and facilitate manual event marking that allows an analyst to delineate exposure or task analysis events on a graphical time line. The software will calculate descriptive summary statistics for risk factor durations and category transitions. Summaries can include data such as the percentage of the work cycle with postures in non-neutral posture categories [99], or counts, durations, and frequency of hand force exertion [100]. One example of such a computer-based method is the MVTA™ [101,102]. MVTA has been used by several investigators to quantify upper limb risk factor levels in detailed observational-based exposure assessment. As an example, Bao et al. [81] described the continuous observation time-based posture analysis as one in which a posture is observed continuously and transitions between angular categories are documented on the timeline. Subsequent processing and analysis results in a distribution of posture among the categories. The advantages of a computerized system to control video playback and perform all of the timekeeping functions for this type of observation and recording of posture are obvious. As a result, computer-based systems such as MVTA are solidifying their place in a number of epidemiologic studies and ergonomic analyses of UECTD risk factors in which more complete exposure profiles are needed. Video exposure monitoring (VEM) is related to computer video–based task analysis and time study. VEM can be broadly defined as the approach whereby a worker’s specific activities can be visualized synchronously with quantitative data on exposure levels or exposure transitions [103–105]. In VEM, the video recording is made synchronously with continuous time exposure sampling, and the exposure level is overlayed graphically on the video image [103]. This was originally accomplished with analog video tape and a variable graphics array (VGA) card or adapter; however, a similar integrated system can now be accomplished with computer software and a digital video camera. An example of a VEM system for visualizing the exertion of hand grip contact force is shown in Figure 32.10. This system was developed on the LabVIEW (National Instruments, Austin, TX) software platform and synchronized data acquisition from thin profile force sensors attached to the palmar surface of the hand with video capture from a consumer video camcorder [106]. Digital video frame grabbing was accomplished through an IEEE bus interface and a custom LabVIEW program which incorporates the Vision Development Module toolkit. In each iteration of the execution loop, a single video frame is grabbed with a sample from 20 force sensors. The frame grab images are appended in sequence to create a video file (.avi file format) in which each frame is synchronized with a force sample. A playback interface allows the viewer to scrub across the force time series trace while the corresponding video frame display is updated.

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FIGURE 32.10  A VEM system that synchronizes video recording with direct measurement of

hand contact force. The playback mode allows for scrolling the cursor across the total hand contact force time series trace (top) to continuously update the corresponding video frame (lower left) and the spatial force distribution representation on the hand (lower right).

32.7 REGULATORY ACTIVITY: OSHA AND NIOSH 32.7.1 Regulatory Activity and OSHA The period of 1995–2000 resulted in a successful effort on the part of the OSHA in drafting and passing an Ergonomics Rule to address MSDs in general industry. In November 1999, OSHA issued a draft standard and the agency made significant changes from the original proposal, after listening to more than 700 witnesses during a nine-week public hearing and reviewing more than 8,000 public comments on the proposal. The final ergonomics program standard appeared in the November 14, 2000 edition of the Federal Register and took effect January 16, 2001. The rule had the following requirements: Management leadership and employee participation: The employer was required to set up an MSD reporting and response system and an ergonomics program and provide supervisors with the responsibility and resources to run the program. The employer was also required to assure that policies encouraged, and did not discourage, employee participation in the program or the reporting of MSD signs, symptoms, and hazards. Employers were required to give employees the opportunity to participate in the development, implementation, and evaluation of the ergonomics program. Job hazard analysis and control: If a job met an Action Trigger, the employer was required to conduct a job hazard analysis to determine whether MSD hazards existed in the job. If hazards were found, the employer was required to implement control measures directed at reducing hazards to the extent “feasible.” Training: The employer was required to provide training to employees in jobs that met the Action Trigger, their supervisors or team leaders and other employees involved in setting

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up and managing the ergonomics program. Training should include the hazards present in the problem job, and the signs and symptoms of the disorders that could result, while also encouraging early reporting of MSDs. MSD management: Employees were to be provided, at no cost, with prompt access to a health care professional (HCP), evaluation and follow-up of an MSD incident, and any temporary work restrictions that the employer or the health care provider determined to be necessary. Work Restriction Protection: Employers were required to provide work restriction protection (WRP) to employees who received temporary work restrictions. This meant maintaining 100% of earnings and full benefits for employees who receive limitations on the work activities in their current job or transfer to a temporary alternative duty job and 90% of earnings and full benefits to employees who were removed from work. WRP was to be good for 90 days, until the employee was able to safely return to the job, or until an HCP determined that the employee was too disabled to ever return to the job, whichever came first. Program evaluation: The employer was required to evaluate their ergonomics program every three years to make sure it is effective. Record keeping: Employers with 11 or more employees, including part-time employees, were required to keep written or electronic records of employee reports of MSDs, MSD signs and symptoms and MSD hazards, responses to such reports, job hazard analyses, hazard control measures, ergonomics program evaluations, and records of work restrictions and the HCP’s written opinions. The OSHA ergonomics rule was short-lived. In March of 2001, under a new administration, the ergonomics rule became the first and, to this date, the only federal regulation to be repealed under the Congressional Review Act, a 1996 bill that gives Congress the power to overturn federal regulations. This bill provided a mechanism for Congressional review and repeal of legislation, and even enables the retroactive repeal of existing legislation within a specific time frame, as was done in this case. Following the 2001 repeal of the ergonomics rule, OSHA’s emphasis shifted to a fourpronged approach which included the development of voluntary ergonomics guidelines, enforcement efforts under the General Duty Clause, outreach and assistance efforts, and the formation of a National Advisory Committee on Ergonomics. The emphasis on voluntary guidelines has resulted in the publication of industry-specific guidelines for nursing homes (2003), poultry processing (2004), retail grocery stores (2004), and shipyards (2008). The repeal of the ergonomics rule in 2001 has not negated OSHAs ability to levy citations to employers with ergonomic hazards in their facilities. In the absence of an industry standard to address ergonomic hazards, OSHA had used, and can continue to use, Section 5(a) (1) of the Occupational Safety and Health Act as the authority to cite. Known as the General Duty Clause, Section 5(a) (1) states that “…each employer shall furnish to each of his employees employment and a place of employment which are free from recognized hazards that are causing or are likely to cause death or serious physical harm to his employees.” Opponents of the ergonomics rule had claimed that such a specific ergonomics regulation

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was unnecessary because the General Duty Clause was a mechanism by which OSHA could regulate for ergonomic hazards. However, since the repeal of the proposed rule in 2001, the number of citations for ergonomic-related hazards has seen a marked decrease. In 2009, OSHA’s Directorate of Enforcement Programs indicated that the agency has issued 19 General Duty Clause citations for ergonomics since 2002. During the same time period, OSHA conducted 4500 ergonomic inspections and issued 640 hazard alert letters on ergonomics. In comparison, during the 10 year period between 1985 and the 1995 first edition of this text, OSHA had issued over 350 citations for either lifting or UECTD hazards. Outreach and assistance efforts have placed emphasis on voluntary protection and a Voluntary Protection Program (VPP) based on incentivizing best practices to meet safety and health goals. However, concerns exist regarding the effectiveness of non-regulatory approaches to incentivizing occupational safety and health efforts, and such concerns may be well founded. Recently, the Government Accountability Office [107] identified OSHA VPP participants with high injury and illness rates—higher in fact than their industry averages. One employer had an injury and illness rate four times higher than the average rate for its industry. In response to this report, OSHA committed to conduct comprehensive evaluation of the VPP. VPP employers are supposed to have exemplary safety records. While participating industries remain subject to OSHA inspections following fatalities, serious injuries, or workers’ complaints about safety or health hazards, they have been exempted from routine inspections. OSHA Alliance programs make up another component of outreach and assistance. These Alliances serve to help industry organizations build trusting, cooperative relationships with OSHA, network with others committed to workplace safety and health, leverage resources to maximize worker safety and health protection, and gain recognition as proactive leaders in safety and health. OSHA currently maintains Alliance Programs with 11 industry organizations (examples include the American Dental Association, American Society of Safety Engineers, Association of Occupational Health Professionals, Association of PeriOperative Registered Nurses, and the Brick Industry Association, among others). These Alliances have led to numerous industry-specific training tools and products. The National Advisory Committee on Ergonomics was chartered in 2003–2004 and made several recommendations to OSHA for its MSD program. In addition to prioritizing the top 16 industries for which ergonomics guidelines should be developed, NACE advised OSHA to consider the following research gaps: • More research is needed to examine the validity of techniques used to establish a diagnosis of MSDs. • More research is needed to examine the role of psychosocial factors that contribute to or impact the development of MSDs. • More studies are needed to develop additional animal models in which the effects of physical loading on living tissues can be studied in a controlled manner.

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• More studies are needed to examine the validity and reliability of existing exposure assessment methods. • More studies are needed to determine the economic impact to organizations of what are commonly described as ergonomic interventions. • More studies are needed to address the multifactorial causes of MSDs, such as psychosocial, physical, occupational, and non-occupational factors, and their interactions. • Additional studies are needed to describe the natural history of diseases or injuries, commonly known as MSDs. • More studies are needed regarding factors in workers’ compensation systems and other statutory payment mechanisms on findings of causation, diagnosis, duration of the disability, and other outcomes related to what are commonly known as MSDs. Two states (California and Washington) have passed ergonomic standards enforceable at the state level. California’s standard went into effect in July 1997 and requires that “…every employer subject to this section shall establish and implement a program designed to minimize repetitive motion injuries (RMIs). The program shall include a worksite evaluation, control of exposures which have caused RMIs and training of employees.” California’s rule applies to a job, process, or operation where an RMI has occurred to two or more employees. Washington state adopted an ergonomics standard in May 2000, with a phased-in enforcement that was scheduled to begin in July 2004. The Washington state standard required employers with “caution zone jobs” to find and fix ergonomic hazards instead of waiting for an injury to occur before taking action. On July 12, 2002, a county court rejected a business coalition’s contention that the state exceeded its authority under state law, acted arbitrarily, and did not follow its rulemaking requirements. During the process of appeal to the state supreme court, Washington state voters passed an initiative in the November 2003 election to repeal the state’s ergonomics standard. Thus, California currently maintains the only ergonomics standard at the state level. 32.7.2 National Occupational Research Agenda The National Occupational Research Agenda (NORA) was unveiled by the NIOSH in 1996 to provide a framework for research collaborations among universities, large and small businesses, professional societies, government agencies, and worker organizations. The NORA team charged with developing a research agenda for workplace MSDs published a report in 2001 [108] documenting the most important research priorities. These priorities included surveillance research, etiologic and medical research, intervention research, and efforts to improve the research process by strengthening communication between researchers and practitioners who apply research. The agenda for improving surveillance research included such objectives as developing userfriendly, standardized workplace surveillance tools; increasing collaboration with federal, state, and non-governmental organizations to encourage comparability of data collection methods; and conducting an ongoing national hazard survey targeting physical workplace factors.

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The research agenda for improving etiologic and medical research included the following: • Refine instruments to detect and quantify the contribution of excessive force, ­awkward posture, movement, and vibration to the disease process. • More clearly define stages of the MSD process, develop precise diagnostic tools, and provide guidelines for effective treatment and return to work. • Clarify the interplay of the factors at different stages of causation, development, and treatment of MSD and measurement of risk factors. Priorities for intervention research included evaluating the effects of the following on the development and prevention of MSDs: • Alternative (product and/or tool) design criteria (force, spatial requirements of work) • Optimization of mechanical work demands, such as force, movement, and posture, and temporal patterns of exposure • Manual handling alternatives in posture, movement, force, productivity, and quality • Ergonomic training and education • Costs and benefits of ergonomic intervention • Evaluate job assignment, selection, and choice on development of MSD • Emerging technologies Now in its second decade, NORA emphasizes meeting the occupational safety and health needs of the eight industry sectors, which are broken out according to the North American Industry Classification System (NAICS) code. Eight sector programs have been established to develop specific agendas that address the occupational safety and health needs of stakeholders in each industry sector. Strategic goals aimed at reducing the prevalence of MSDs for the low back and upper extremities are evident in all sectors. Upper limb CTDs have been identified as a high priority across all industry sectors.

32.8 FUTURE CONCERNS If recent history is a good predictor, the regulatory landscape with respect to ergonomics and MSDs will continue to be shaped largely by political and economic factors. These factors are difficult to project beyond the short term, and it is difficult to predict the likelihood, much less the scope, of future regulatory activity affecting workplace prevention of UECTDs. However, there are clear trends in the U.S. workforce and labor market that can be anticipated to impact the way ergonomics professionals approach their discipline. The first, and most quantifiable, trend is the aging U.S. workforce. During the period 2006–2016, the number of workers aged 55–64 is expected to increase by 36.5%, and the number of workers over age 65 will increase by more than 80%. This will continue the

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current trend in which older workers make up a progressively larger percentage of the labor force. A ­second trend is the diversification of the workforce. Among those over 65 years of age, the percentage growth of women in the workforce greatly exceeds that of men. These changes in the demographics of the labor force underscore the need to consider the physical capabilities, such as strength, range of motion, dexterity, anthropometry, and metabolic work capacity of the specific worker population of interest. No less significant of a future concern is the changing nature of work in U.S. industry. The way that work is organized affects exposures to physical and psychosocial risk factors for UECTDs. Automation and enhancements in process efficiency may result in a reduction of the highest biomechanical loads on the worker imposed by the gross handling of materials, but the positive effects of such automation may be negated by a resulting increased pace of work. It has been suggested that workplace exposures are shifting to less forceful but more frequent motions [109] performed in less-conventional environments. With increases in the service sector and warehousing distribution-related industries, fewer workers as a percentage of the labor force are employed in jobs organized around the traditional manufacturing assembly line. Physical exposures may be more difficult to assess in jobs with the characteristics observed in these sectors. Evidence suggests that the changing nature of work has served to increase psychosocial stressors in the workplace. These stressors continue to be on the rise, driven by trends toward globalization, outsourcing, “right-sizing,” longer work hours, and decreased job security for many workers. A growing body of evidence implicates psychosocial stresses in the etiology of UECTDs. Trends toward non-traditional and flexible employment practices have raised concerns about the effect of such practices on worker safety and health. According to data from the BLS Current Population Survey, agency-supplied temporary workers and workers in other alternative employment arrangements (independent contractors, contractor-supplied labor, day laborers, and on-call workers) accounted for nearly 10% of the workforce in 2001 and represent a growing percentage of the labor force. The Current Employment Statistics Survey (CES) showed, for example, that the total number of jobs in the temporary help industry multiplied sixfold (to nearly 3 million) during the period 1982–1998, whereas total employment during this period grew by only 40%. It has been suggested that flexible employment practices are leading to a downward restructuring of the labor market with the temporary labor force becoming the group exposed to the most severe workplace hazards and health risks. This group of workers is the least trained to recognize and report ergonomic workplace hazards and CTD risk factors, the least protected by benefits and traditional employer obligations under labor law, and the most difficult for which to track physical exposure and prevalence of UECTDs. This may increase the difficulty of accurately representing the scope of UECTD problems in the workplace.

ACKNOWLEDGMENT The author would like to acknowledge the work of Daniel Habes, author of the Upper Extremity Cumulative Trauma Disorders chapter in the first edition of Occupational Ergonomics: Theory and Application. Some portions of the first edition chapter, written

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by Mr. Habes, have been preserved in this second edition. The assistance of John Sestito (NIOSH, Division of Surveillance, Hazard Evaluation, and Field Studies) is greatly appreciated, as is that of Steve Wurzelbacher (NIOSH), Jim Maddux (OSHA), Joanna Sznajder (OSHA), and Amit Bhattacharya who commented on a draft version of this chapter.

REFERENCES 1. National Institute for Occupational Safety and Health (NIOSH), Proposed National Strategies for the Prevention of Leading Work-Related Diseases and Injuries, Part 1, 1986. 2. F.T. McDermott, Repetition strain injury: A review of current understanding, Med J Aust, 144(4), 196–200 (1986). 3. W.E. Stone, Occupational overuse syndrome in other countries, J Occup Health Safety-Aust, 3(4), 397–404 (1986). 4. G. Rosen, The worker’s hand, Ciba Symp, 4(4), 1307–1322 (1942). 5. F. Gerr, R. Letz, and P.J. Landrigan, Upper-extremity musculoskeletal disorders of occupational origin, Annu Rev Public Health, 12, 543–566 (1991). 6. W. Singleton, The Body at Work: Biological Ergonomics, Cambridge, U.K.: Cambridge University Press, 1982. 7. L.A. MacDonald, R.A. Karasek, L. Punnett, and T. Scharf, Covariation between workplace physical and psychosocial stressors: Evidence and implications for occupational health research and prevention, Ergonomics, 44(7), 696–718 (2001). 8. K.G. Parker, and H.R. Imbus, Cumulative Trauma Disorders, Chelsea, MI: Lewis Publishers, 1992. 9. I. Kuorinka and L. Forcier, Work Related Musculoskeletal Disorders (WMSDs): A Reference Book for Prevention, London, U.K.: Taylor & Francis Group, 1995. 10. A. Joyce, For Some, Thumb Pain Is BlackBerry’s Stain, The Washington Post, April 23, 2005. 11. American Society of Hand Therapists (ASHT), National Consumer Education Alert: Heavy Use of Handheld Electronics Such as Blackberry, iPod Can Lead to Hand Ailments: January 25, 2005. 12. C. Dillon, M. Petersen, and S. Tanaka, Self-reported hand and wrist arthritis and occupation: Data from the U.S. National Health Interview Survey-Occupational Health Supplement, Am J Ind Med, 42(4), 318–327 (2002). 13. W. Brain, A. Wright, and M. Wilkinson, Spontaneous compression of both median nerves in the carpal tunnel, Lancet 1, 277–282, 1947. 14. R.C. Tanzer, The carpal tunnel syndrome., Clin Orthop, 15, 171–179 (1959). 15. T.J. Armstrong and D.B. Chaffin, Carpal tunnel syndrome and selected personal attributes, J Occup Med, 21(7), 481–486 (1979). 16. E.R. Tichauer, Some aspects of stress on forearm and hand in industry, J Occup Med, 8(2), 63–71 (1966). 17. R. Muckart, Stenosing tendovaginitis of abductor pollicis longus and extensor pollicis brevis at the radial styloid (DeQuervain’s disease), Clin Orthop Relat Res, 33, 201–208 (1964). 18. B.A. Silverstein, L.J. Fine, and T.J. Armstrong, Occupational factors and carpal tunnel syndrome, Am J Ind Med, 11(3), 343–358 (1987). 19. L. Hymovich and M. Lindholm, Hand, wrist, and forearm injuries. The result of repetitive motions, J Occup Med, 8(11), 573–577 (1966). 20. H. Ohara, S. Nakagiri, T. Itani, K. Wake, and H. Aoyama, Occupational health hazards resulting from elevated work rate situations, J Hum Ergol (Tokyo), 5(2), 173–182 (1976). 21. W.F. Fox, Human performance in the cold, Hum Factors, 9(3), 203–220 (1967). 22. J.M. Lockhart and H.O. Kiess, Auxiliary heating of the hands during cold exposure and manual performance, Hum Factors, 13(5), 457–465 (1971). 23. L.J. Cannon, E.J. Bernacki, and S.D. Walter, Personal and occupational factors associated with carpal tunnel syndrome, J Occup Med, 23(4), 255–258 (1981).

Cumulative Trauma Disorders of the Upper Extremities    ◾    881   24. R.G. Radwin, T.J. Armstrong, and D.B. Chaffin, Power hand tool vibration effects on grip exertions, Ergonomics, 30, 833–855 (1987). 25. M.L. Bleecker, Medical surveillance for carpal tunnel syndrome in workers, J Hand Surg Am, 12(5 Pt 2), 845–848, (1987). 26. V. Putz-Anderson, Cumulative Trauma Disorders: A Manual for Musculoskeletal Diseases of the Upper Limbs, London; New York: Taylor & Francis Group, 1988. 27. T.F. Morse, C. Dillon, N. Warren, C. Levenstein, and A. Warren, The economic and social consequences of work-related musculoskeletal disorders: The Connecticut Upper-Extremity Surveillance Project (CUSP), Int J Occup Environ Health, 4(4), 209–216 (1998). 28. World Health Organization (WHO), Identification and control of work-related diseases, (WHO Technical Report Series No. 714), 1985. 29. B. Bernard, Musculoskeletal disorders and workplace factors: A critical review of epidemiologic evidence for work-related musculoskeletal disorders of the neck, upper extremity, and low back, DHHS(NIOSH) Pub. No. 97–141, 1997. 30. National Research Council and the Institute of Medicine, Musculoskeletal Disorders and the Workplace: Low Back and Upper Extremities, Panel on Musculoskeletal Disorders and the Workplace, Commission on Behavioral and Social Sciences and Education, Washington, DC: National Academy Press, 2001. 31. C.G. Barnes and H.L.F. Currey, Carpal tunnel syndrome in rheumatoid arthritis, a clinical and electrodiagnostic survey, Ann Rheum Dis, 26, 226–233 (1967). 32. M.S. Sabour and H.H. Fadel, The carpal tunnel syndrome–A new complication ascribed to the pill, Am J Obstet Gynecol, 107(3), 1265–1267 (1979). 33. S. Lozano-Calderon, S. Anthony, and D. Ring, The quality and strength of evidence for etiology: Example of carpal tunnel syndrome, J Hand Surg Am, 33(4), 525–538 (2008). 34. K.T. Palmer, E.C. Harris, and D. Coggon, Carpal tunnel syndrome and its relation to occupation: A systematic literature review, Occup Med (Lond), 57(1), 57–66 (2007). 35. B.A. Hill, The environment and disease: Association or causation? Proc R Soc Med, 58, 295–300 (1965). 36. L. Punnett and D.H. Wegman, Work-related musculoskeletal disorders: The epidemiologic evidence and the debate, J Electromyogr Kinesiol, 14(1), 13–23 (2004). 37. Bureau of Labor Statistics, Annual Survey of Occupational Injuries and Illnesses, Washington, DC: U.S. Department of Labor, 2007. 38. T. Morse, C. Dillon, E. Kenta-Bibi, J. Weber, U. Diva, N. Warren, et al., Trends in work-related musculoskeletal disorder reports by year, type, and industrial sector: A capture-recapture analysis, Am J Ind Med, 48(1), 40–49 (2005). 39. K.D. Rosenman, A. Kalush, M.J. Reilly, J.C. Gardiner, M. Reeves, and Z. Luo, How much workrelated injury and illness is missed by the current national surveillance system? J Occup Environ Med, 48(4), 357–365 (2006). 40. J.C. Rosecrance, T.M. Cook, D.C. Anton, and L.A. Merlino, Carpal tunnel syndrome among apprentice construction workers, Am J Ind Med, 42(2), 107–116 (2002). 41. L.S. Friedman and L. Forst, The impact of OSHA recordkeeping regulation changes on occupational injury and illness trends in the US: A time-series analysis, Occup Environ Med, 64(7), 454–460 (2007). 42. T.L. Holbrook, K. Grazier, J.L. Kelsey, and R.N. Stauffer, The frequency of occurrence, impact and cost of selected musculoskeletal conditions in the United States, Chicago, IL: American Academy of Orthopadic Surgeons, 1984. 43. K.D. Rosenman, J.C. Gardiner, J. Wang, J. Biddle, A. Hogan, M.J. Reilly, et al., Why most workers with occupational repetitive trauma do not file for workers’ compensation, J Occup Environ Med, 42(1), 25–34 (2000). 44. D.E. Elisburg, Cumulative Trauma Disorders in the Workplace: Costs, Prevention, and Progress, Washington, DC: Bureau of National Affairs (BNA), 1991.

882    ◾    Occupational Ergonomics: Theory and Applications 45. G. Brogmus and R. Marko, The proportion of cumulative trauma disorders of the upper extremities in U.S. industry, Paper Presented at the Human Factors Society 36th Annual Meeting, Atlanta, GA, 1992. 46. Safety & Health Assessment & Research for Prevention (SHARP), Work-related Musculoskeletal Disorders of the Neck, Back, and Upper Extremity in Washington State, 1997–2005, Technical Report No. 40-11-2007, Olympia, WA: SHARP Program, 2007. 47. B. Juul-Kristensen, N. Fallentin, and C. Ekdahl, Criteria for classification of posture in repetitive work by observation methods: A review, Int J Ind Ergon, 19, 397–411 (1997). 48. C. Hamrick, Overview of Ergonomic Assessment (2nd edn.), Boca Raton, FL: CRC/Taylor & Francis Group, 2006. 49. W.M. Keyserling, D.S. Stetson, B.A. Silverstein, and M.L. Brouwer, A checklist for evaluating ergonomic risk factors associated with upper extremity cumulative trauma disorders, Ergonomics, 36(7), 807–831 (1993). 50. K. Kemmlert, A method assigned for the identification of ergonomic hazards—PLIBEL, Appl Ergon, 26(3), 199–211 (1995). 51. G. Li and P. Buckle, Current techniques for assessing physical exposure to work-related musculoskeletal risks, with emphasis on posture-based methods, Ergonomics, 42, 674–695 (1999). 52. Washington State Department of Labor and Industries, Pocket Guide to Caution Zone Jobs, 2003. 53. ANSI/ASSE, Reduction of Musculoskeletal Problems in Construction and Demolition Operations, ANSI/ASSE A10.40-2007, 2007. 54. NIOSH/Cal-OSHA, Easy Ergonomics: A Guide to Selecting Non-Powered Hand Tools, DHHS (NIOSH) Publication No. 2004-16, 2004. 55. A. Dababneh, B. Lowe, E. Krieg, Y.K. Kong, and T. Waters, Ergonomics: A checklist for the ergonomic evaluation of nonpowered hand tools, J Occup Environ Hyg, 1(12), D135–D145 (2004). 56. A. Kilbom, Assessment of physical exposure in relation to work-related musculoskeletal disorders–What information can be obtained from systematic observations? Scand J Work Environ Health, 20 Spec No, 30–45 (1994). 57. G. David, Ergonomic methods for assessing exposure to risk factors for work-related musculoskeletal disorders, Soc Occupational Med, 55, 190–199 (2005). 58. J.S. Moore and A. Garg, The strain index: A proposed method to analyze jobs for risk of distal upper extremity disorders, Am Ind Hyg Assoc J, 56(5), 443–458 (1995). 59. American Conference of Governmental Industrial Hygienists (ACGIH), Documentation of the TLVs and BEIs (6th edn.), Cincinnati, OH: ACGIH Worldwide, 2005. 60. T. Armstrong, M. Ebersole, A. Franzblau, S. Ulin, and R. Werner, The ACGIH TLV: A review of some recent studies, Paper presented at the 2006 International Ergonomics Association Triennial Congress, Maastricht, the Netherlands, 2006. 61. G. Borg, A category scale with ratio properties for intermodal and interindividual comparisons, In H.G. Geissler and P. Petzold (eds.), Psychophysical Judgment and the Process of Perception, Berlin, Germany: VEB Deutscher Verlag Der Wissenschaften, 1982. 62. S. Bao and B. Silverstein, Estimation of hand force in ergonomic job evaluations, Ergonomics, 48(3), 288–301 (2005). 63. W.A. Latko, T.J. Armstrong, A. Franzblau, S.S. Ulin, R.A. Werner, and J.W. Albers, Crosssectional study of the relationship between repetitive work and the prevalence of upper limb musculoskeletal disorders, Am J Ind Med, 36(2), 248–259 (1999). 64. D. Colombini, An observational method for classifying exposure to repetitive movements of the upper limbs, Ergonomics, 41(9), 1261–1289 (1998). 65. E. Occhipinti, OCRA: A concise index for the assessment of exposure to repetitive movements of the upper limbs, Ergonomics, 41(9), 1290–1311 (1998). 66. T.R. Waters, V. Putz-Anderson, A. Garg, and L.J. Fine, Revised NIOSH equation for the design and evaluation of manual lifting tasks, Ergonomics, 36(7), 749–776 (1993).

Cumulative Trauma Disorders of the Upper Extremities    ◾    883   67. NIOSH, A Work Practices Guide to Manual Lifting, Technical Report No. 81–122, Cincinnati, OH: U.S. Department of Health and Human Services (NIOSH), 1981. 68. V. Seth, R.L. Weston, and A. Freivalds, Development of a cumulative trauma disorder risk assessment model for the upper extremities, Int J Ind Ergon, 23, 281–291 (1999). 69. B.W. Niebel and A. Freivalds, Methods, Standards, and Work Design (11th edn.), Dubuque, IA: McGraw-Hill, 2003. 70. O. Karhu, P. Kansi, and I. Kuorinka, Correcting working postures in industry. A practical method for analysis, Appl Ergon, 8, 199–201 (1977). 71. L. McAtamney and E.N. Corlett, RULA: A survey method for the investigation of work-related upper limb disorders, Appl Ergon, 24(2), 91–99 (1993). 72. S. Hignett and L. McAtamney, Rapid entire body assessment (REBA), Appl Ergon, 31(2), 201– 205 (2000). 73. D. Kee and W. Karwowski, An Assessment Technique for Postural Loading on the Upper Body (LUBA) (2nd edn.), Boca Raton, FL: CRC/Taylor & Francis Group, 2006. 74. A.M. Genaidy, A.A. Al-Shedi, and W. Karwowski, Postural stress analysis in industry, Appl Ergon, 25(2), 77–87 (1994). 75. A. Buchholz, V. Paquet, L. Punnett, D. Lee, and S. Moir, PATH: A work sampling-based approach to ergonomic job analysis for construction and other non-repetitive work, Appl Ergon, 27(3), 177–187 (1996). 76. V.L. Paquet, L. Punnett, and B. Buchholz, Validity of fixed-interval observations for postural assessment in construction work, Appl Ergon, 32(3), 215–224 (2001). 77. K. Knox and J.S. Moore, Predictive validity of the strain index in turkey processing, J Occup Environ Med, 43(5), 451–462 (2001). 78. N. Rucker and J.S. Moore, Predictive validity of the strain index in manufacturing facilities, Appl Occup Environ Hyg, 17(1), 63–73 (2002). 79. A. Franzblau, T.J. Armstrong, R.A. Werner, and S.S. Ulin, A cross-sectional assessment of the ACGIH TLV for hand activity level, J Occup Rehabil, 15(1), 57–67 (2005). 80. P. Spielholz, S. Bao, N. Howard, B. Silverstein, J. Fan, C. Smith, et al., Reliability and validity assessment of the hand activity level threshold limit value and strain index using expert ratings of mono-task jobs, J Occup Environ Hyg, 5(4), 250–257 (2008). 81. S. Bao, N. Howard, P. Spielholz, and B. Silverstein, Quantifying repetitive hand activity for epidemiological research on musculoskeletal disorders–Part II: Comparison of different methods of measuring force level and repetitiveness, Ergonomics, 49(4), 381–392 (2006). 82. B.D. Lowe, Accuracy and validity of observational estimates of shoulder and elbow posture, Appl Ergon, 35(2), 159–171 (2004). 83. P.M. van Wyk, P.L. Weir, D.M. Andrews, K.M. Fiedler, and J.P. Callaghan, Determining the ­optimal size for posture categories used in video-based posture assessment methods, Ergonomics, 52(8), 921–930 (2009). 84. S. Bao, N. Howard, P. Spielholz, B. Silverstein, and N. Polissar, Interrater reliability of posture observations, Hum Factors, 51(3), 292–309 (2009). 85. B. DeLuca, The use of surface electromyography in biomechanics, J Appl Biomech, 13, 135–163 (1997). 86. G.M. Hagg, A. Luttmann, and M. Jager, Methodologies for evaluating electromyographic field data in ergonomics, J Electromyogr Kinesiol, 10(5), 301–312 (2000). 87. M.J. Hoozemans and J.H. van Dieen, Prediction of handgrip forces using surface EMG of forearm muscles, J Electromyogr Kinesiol, 15(4), 358–366 (2005). 88. S.E. Mathiassen and J. Winkel, Quantifying variation in physical load using exposure-vs-time data, Ergonomics, 34, 1455–1468 (1991). 89. D. Anton, T.M. Cook, J.C. Rosecrance, and L.A. Merlino, Method for quantitatively assessing physical risk factors during variable noncyclic work, Scand J Work Environ Health, 29(5), 354–362 (2003).

884    ◾    Occupational Ergonomics: Theory and Applications 90. B. Jonsson, Quantitative electromyographic evaluation of muscular load during work, Scand J Rehabil Med, 6, 69–74 (1978). 91. R.W. McGorry, A system for the measurement of grip forces and applied moments during hand tool use, Appl Ergon, 32(3), 271–279 (2001). 92. G.L. Fellows, and A. Freivalds, Ergonomics evaluation of a foam rubber grip for tool handles, Appl Ergon, 22(4), 225–230 (1991). 93. R.G. Radwin, S. Oh, T.R. Jensen, and J.G. Webster, External finger forces in submaximal fivefinger static pinch prehension, Ergonomics, 35(3), 275–288 (1992). 94. Y.K. Kong and B.D. Lowe, Optimal cylindrical handle diameter for grip force tasks, Int J Ind Ergon, 35(6), 495–507 (2005). 95. J.T. Albers and S.D. Hudock, Biomechanical assessment of three rebar tying techniques, Int J Occup Saf Ergon, 13(3), 279–289 (2007). 96. P.G. Dempsey, R.W. McGorry, and W.S. Maynard, A survey of tools and methods used by certified professional ergonomists, Appl Ergon, 36(4), 489–503 (2005). 97. C. Coffey, NIOSH Seeks Input on Direct Reading Exposure Assessment Methods (D.R.E.A.M.) Workshop, Washington, DC, 2009 (September 4, 2009). 98. W.M. Keyserling, Postural analysis of the trunk and shoulders in simulated real time, Ergonomics, 29(4), 569–583 (1986). 99. A. Dartt, J. Rosecrance, F. Gerr, P. Chen, D. Anton, and L. Merlino, Reliability of assessing upper limb postures among workers performing manufacturing tasks, Appl Ergon, 40(3), 371–378 (2009). 100. S. Wurzelbacher, S. Burt, K. Crombie, J. Ramsey, L. Luo, S. Allee, et al., A comparison of assessment methods of hand activity and force for use in calculating the ACGIH TLV, J Occup Environ Hygiene, 7(7), 407–416 (2010). 101. T.Y. Yen and R.G. Radwin, A video-based system for acquiring biomechanical data synchronized with arbitrary events and activities, IEEE Trans Biomed Eng, 42(9), 944–948 (1995). 102. T.Y. Yen and R.G. Radwin, Multimedia video-based data acquisition and analysis applications for ergonomics research, Paper Presented at the XIVth Triennial Congress of the International Ergonomics Association and 44th Annual Meeting of the Human Factors and Ergonomics Society, San Diego, CA, 2000. 103. J.D. McGlothlin, M.G. Gressel, W.A. Heitbrink, and P.A. Jensen, Real-time exposure assessment and job analysis techniques to solve hazardous workplace exposures, in A. Bhattacharya and J.D. McGlothlin (eds.), Occupational Ergonomics: Theory and Applications (pp. xiv, 832 p), New York: Marcel Dekker, 1996. 104. J.D. McGlothlin, Occupational exposure visualization comes of age, Ann Occup Hyg, 49(3), 197–199 (2005). 105. G. Rosen, I.M. Andersson, P.T. Walsh, R.D. Clark, A. Saamanen, K. Heinonen, et al., A review of video exposure monitoring as an occupational hygiene tool, Ann Occup Hyg, 49(3), 201–217 (2005). 106. B.D. Lowe, Y. Kong, and J. Han, Development and application of a hand force measurement system, Proceedings of the XVIth Triennial Congress of the International Ergonomics Association, Maastricht, the Netherlands: Triennial Congress of the International Ergonomics Association, 2006. 107. Government Accountability Office (GAO), OSHA’s Voluntary Protection Programs: Improved Oversight and Controls Would Better Ensure Program Quality, May 2009. GAO-09-395, 2009. 108. NIOSH, National Occupational Research Agenda for Musculoskeletal Disorders: Research Topics for the Next Decade, A Report by the NORA Musculoskeletal Disorders Team, DHHS (NIOSH) Publication No. 2001-117, 2001.

Cumulative Trauma Disorders of the Upper Extremities    ◾    885   109. W.S. Marras, R.G. Cutlip, S.E. Burt, and T.R. Waters, National occupational research agenda (NORA) future directions in occupational musculoskeletal disorder health research, Appl Ergon, 40, 15–22 (2009). 110. M. DiNatale, Characteristics of and preference for alternative work arrangements, 1999, Mon Labor Rev, 124(3), 28–49 (2001). 111. J.P. Stephens, G.A. Vos, E.M. Stevens Jr., and J.S. Moore, Test-retest repeatability of the strain index, Appl Ergon, 37(3), 275–281 (2006). 112. E.M. Stevens, G.A. Vos, J.P. Stephens, and J.S. Moore, Inter-rater reliability of the strain index, J Occup Environ Hyg, 1(11), 745–751 (2004).

Chapter

33

Revised NIOSH Lifting Equation Thomas R. Waters CONTENTS 33.1 Introduction 33.2 Definition of Terms 33.2.1 Recommended Weight Limit 33.2.2 Measurement Requirements 33.2.3 Lifting Index 33.2.4 Miscellaneous Terms 33.3 Limitations of the Equation 33.4 Obtaining and Using the Data 33.4.1 Horizontal Component 33.4.1.1 Definition and Measurement 33.4.1.2 Horizontal Restrictions 33.4.1.3 Horizontal Multiplier 33.4.2 Vertical Component 33.4.2.1 Definition and Measurement 33.4.2.2 Vertical Restrictions 33.4.2.3 Vertical Multiplier 33.4.3 Distance Component 33.4.3.1 Definition and Measurement 33.4.3.2 Distance Restrictions 33.4.3.3 Distance Multiplier 33.4.4 Asymmetry Component 33.4.4.1 Definition and Measurement 33.4.4.2 Asymmetry Restrictions 33.4.4.3 Asymmetric Multiplier 33.4.5 Frequency Component 33.4.5.1 Definition and Measurement 33.4.5.2 Lifting Duration

888 889 889 890 891 891 893 894 894 894 895 895 895 895 895 895 896 896 896 897 897 897 898 898 899 899 899 887

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33.4.5.3 Frequency Restrictions 33.4.5.4 Frequency Multiplier 33.4.6 Coupling Component 33.4.6.1 Definition and Measurement 33.4.6.2 Coupling Multiplier 33.5 Procedures 33.5.1 Single-Task Job 33.5.2 Multitask Job 33.5.3 Sequential Lifting Job 33.5.4 Variable Lifting Job 33.5.4.1 Lifting Index for Single-Task Jobs 33.5.4.2 Composite Lifting Index for Multitask Jobs 33.5.4.3 Sequential Lifting Index 33.5.4.4 Variable Lifting Index 33.6 Applying the Equations 33.6.1 Using RWL and LI, CLI, SLI, and VLI to Guide Ergonomic Design 33.6.2 Rationale and Limitations for Lifting Index Values (LI, CLI, SLI, and VLI) 33.6.3 Job-Related Intervention Strategy 33.6.4 Example Problems References

902 902 902 902 902 902 903 903 904 904 905 906 910 913 915 915 916 916 916 922

33.1 INTRODUCTION This chapter provides information about a revised equation for assessing the physical demands of certain two-handed manual lifting tasks that was developed by the National Institute for Occupational Safety and Health (NIOSH) and described earlier in an article by Waters et al. [1]. We discuss what factors need to be measured, how they should be measured, what procedures should be used, and how the results can be used to ergonomically design new jobs or make decisions about redesigning existing jobs that may be hazardous. We define all pertinent terms and present the mathematical formulas and procedures needed to properly apply the NIOSH lifting equation. Several example problems are also provided to demonstrate how the equations should be used. An expanded version of this chapter is contained in an NIOSH report [2]. Historically, NIOSH has recognized the problem of work-related back injuries resulting from manual lifting and, in response, published the Work Practices Guide for Manual Lifting (WPG) in 1981 [3]. The WPG contained a summary of the lifting-related literature up to 1981; analytical procedures and a lifting equation for calculating a recommended weight for specific two-handed, symmetrical lifting tasks; and an approach for controlling the hazards of low back injury from manual lifting. The approach to hazard control was coupled to the action limit (AL), a term that denoted the recommended weight derived from the lifting equation. In 1985, NIOSH convened an ad hoc committee of experts who reviewed the current literature on lifting, with a special focus on the original NIOSH WPG.* The literature review * The ad hoc 1991 NIOSH Lifting Committee members included M. M. Ayoub, Donald B. Chaffin, Colin G. Drury, Arun Garg, and Suzanne Rodgers. NIOSH representatives included Vern Putz-Anderson and Thomas R. Waters.

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was summarized in a document containing updated information on the physiological, biomechanical, psychophysical, and epidemiological aspects of manual lifting [4]. Based on the results of the literature review, the ad hoc committee recommended criteria for defining the lifting capacity of healthy workers. The committee used the criteria to formulate the revised lifting equation.* Subsequently, NIOSH staff developed the documentation for the equation and played a prominent role in recommending methods for interpreting the results of the lifting equation. The revised lifting equation reflects new findings and provides methods for evaluating asymmetrical lifting tasks and lifts of objects with less than optimal couplings between the object and the worker’s hands. The revised lifting equation also provides guidelines for a more diverse range of lifting tasks than the earlier equation [3]. The rationale and criterion for the development of the revised NIOSH lifting equation (RNLE) are provided in a journal article by Waters et al. [1]. We suggest that those users who wish to achieve a better understanding of the data and decisions that were made in formulating the RNLE consult that article. It provides an explanation of the selection of the biomechanical, physiological, and psychophysical criterion as well as a description of the derivation of the individual components of the RNLE. For those individuals, however, who are primarily concerned with the use and application of the RNLE, this chapter provides a more complete description of the method and its limitations. Although the RNLE has not been fully validated, the recommended weight limits (RWLs) derived from the RNLE are consistent with, or lower than, those generally reported in the literature [1]. Moreover, the proper application of the RNLE is more likely to protect healthy workers for a wider variety of lifting tasks than methods that rely on only a singletask factor or single criterion. Finally, it should be stressed that the NIOSH lifting equation is only one tool in a comprehensive effort to prevent work-related low back pain (LBP) and disability. Some examples of other approaches are described elsewhere [5]. Moreover, lifting is only one of the causes of work-related LBP and disability. Other causes that have been hypothesized or established as risk factors include whole body vibration, static postures, prolonged sitting, and direct trauma to the back. Psychosocial factors, appropriate medical treatment, and job demands may also be particularly important in influencing the transition of acute LBP to chronic disabling pain.

33.2 DEFINITION OF TERMS This section provides the basic technical information needed to properly use the RNLE to evaluate a variety of two-handed manual lifting tasks. Definitions and data requirements for the RNLE are also provided. 33.2.1 Recommended Weight Limit The RWL is the principal product of the RNLE. The RWL is defined for a specific set of task conditions as the weight of the load that nearly all healthy workers could perform * For this remainder of this chapter, the revised 1991 NIOSH lifting equation will be identified simply as “the RNLE” [1,2]. The abbreviation WPG will continue to be used as the reference to the earlier NIOSH lifting equation, which was documented in the Work Practices Guide for Manual Lifting [3].

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over a substantial period of time (e.g., up to 8 h) without an increased risk of developing lifting-related LBP. By “healthy workers” we mean workers who are free of adverse health conditions that would increase their risk of musculoskeletal injury. The concept behind the RNLE is to start with a recommended weight that is considered safe for an “ideal” lift (i.e., load constant equal to 51 lb) and then reduce the weight as the task becomes more stressful (i.e., as the task-related factors become less favorable). The precise formulation of the RNLE for calculating the RWL is based on a multiplicative model that provides a weighting (multiplier) for each of six task variables: 1. Horizontal distance of the load from the worker (H) 2. Vertical height of the lift (V) 3. Vertical displacement during the lift (D) 4. Angle of asymmetry (A) 5. Frequency (F) and duration of lifting 6. Quality of the hand-to-object coupling (C) The weightings are expressed as coefficients that serve to decrease the load constant, which represents the maximum recommended load weight to be lifted under ideal conditions. For example, as the horizontal distance between the load and the worker increases from 10 in., the RWL for that task would be reduced from the ideal starting weight. The RWL is defined as

RWL = LC × HM × VM × DM × AM × FM × CM

where the term task variables refers to the measurable task-related measurements that are used as input data for the formula (i.e., H, V, D, A, F, and C), whereas the term multipliers refers to the reduction coefficients in the equation (i.e., HM, VM, DM, AM, FM, and CM). 33.2.2 Measurement Requirements The following list briefly describes the measurements required to use the RNLE. Details for each of the variables are presented later in this chapter (see Section 33.4): H is the horizontal location of hands from midpoint between the inner ankle bones. H should be measured at the origin and the destination of the lift (cm or in.). V is the vertical location of the hands from the floor. V should be measured at the origin and destination of the lift (cm or in.). D is the vertical travel distance between the origin and the destination of the lift (cm or in.). A is the angle of asymmetry—angular displacement of the load from the worker’s sagittal plane. A should be measured at the origin and destination of the lift (degrees).

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F is the average frequency rate of lifting measured in lifts/min. Duration is defined to be ≤1 h, ≤2 h, or ≤8 h assuming appropriate recovery allowances (see Table 33.5). C is the quality of hand-to-object coupling (quality of interface between the worker and the load being lifted). The quality of the coupling is categorized as good, fair, or poor, depending upon the type and location of the coupling, the physical characteristics of load, and the vertical height of the lift. 33.2.3 Lifting Index The lifting index (LI) is a term that provides a relative estimate of the level of physical stress associated with a particular manual lifting task. The estimate of the level of physical stress is defined by the relationship between the weight of the load lifted and the RWL. The LI is defined by the equation



LI =

load weight L = recommended weight limit RWL

where load weight (L) is the weight of the object lifted (lb or kg). 33.2.4 Miscellaneous Terms Lifting task: The act of manually grasping an object of definable size and mass with two hands and vertically moving the object without mechanical assistance. Load weight (L): Weight of the object to be lifted, in pounds or kilograms, including the container. Horizontal location (H): Distance of the hands away from the midpoint between the ankles, in inches or centimeters (measure at the origin and destination of lift). See Figure 33.1. Vertical location (V): Distance of the hands above the floor, in inches or centimeters (measure at the origin and destination of lift). See Figure 33.1. Vertical travel distance (D): Absolute value of the difference between the vertical heights at the destination and origin of the lift, in inches or centimeters. Angle of asymmetry (A): Angular measure of how far the object is displaced from the front (midsagittal plane) of the worker’s body at the beginning or end of the lift, in degrees (measure at the origin and destination of lift). See Figure 33.2. The asymmetry angle is defined by the location of the load relative to the worker’s midsagittal plane, as defined by the neutral body posture, rather than the position of the feet or the extent of body twist. Neutral body position: Position of the body when the hands are directly in front of the body and there is minimal twisting at the legs, torso, or shoulders.

892    ◾    Occupational Ergonomics: Theory and Applications Vertical Point of projection

Top view

Horizontal Horizontal H location Lateral Mid-point between inner ankle bones

V

Vertical location

Horizontal Mid-point between inner ankle bones

H Horizontal location

Point of projection

FIGURE 33.1  Graphic representation of hand location.

Frequency of lifting (F): Average number of lifts per minute over a 15 min period. Duration of lifting: Three-tiered classification of lifting duration specified by the distribution of work time (WT) and recovery time (work pattern). Duration is classified as either short (1 h), moderate (1–2 h), or long (2–8 h), depending on the work pattern. Coupling classification: Classification of the quality of the hand-to-object coupling (e.g., handle, cutout, or grip). Coupling quality is classified as good, fair, or poor. Significant control: A condition requiring “precision placement” of the load at the destination of the lift. This is usually the case when (1) the worker has to regrasp the load near the destination of the lift, (2) the worker has to momentarily hold the object at the destination, or (3) the worker has to carefully position or guide the load at the destination.

Revised NIOSH Lifting Equation    ◾    893   Sagittal plane

Sagittal Mid-point between inner ankle bones

Top view

Frontal Point of projection

H A

Frontal plane

Point of projection

Asymmetry line

A Asymmetric angle

Sagittal line

FIGURE 33.2  Graphic representation of angle of asymmetry (A).

33.3 LIMITATIONS OF THE EQUATION The lifting equation is a tool for assessing the physical stress of two-handed manual lifting tasks. As with any tool, its application is limited to those conditions for which it was designed. Specifically, the lifting equation was designed to meet specific lifting-related criteria that encompass biomechanical, physiological, and psychophysical assumptions and data used to develop the equation. To the extent that a given lifting task accurately reflects these underlying conditions and criteria, this lifting equation may be appropriately applied. The following list identifies a set of work conditions in which the application of the lifting equation could either under- or overestimate the extent of physical stress associated with a particular work-related activity. Each of the following task limitations also highlights research topics in need of further research to extend the application of the lifting equation to a greater range of real-world lifting tasks.

894    ◾    Occupational Ergonomics: Theory and Applications

The RNLE does not apply if any of the following occur: Lifting/lowering with one hand Lifting/lowering for over 8 h Lifting/lowering while seated or kneeling Lifting/lowering in a restricted workspace Lifting/lowering unstable objects Lifting/lowering while carrying, pushing, or pulling Lifting/lowering with wheelbarrows or shovels Lifting/lowering with “high-speed” motion (faster than about 30 in./s) Lifting/lowering with unreasonable foot/floor coupling (25

1.00 0.91 0.83 0.77 0.71 0.67 0.63 0.59 0.56 0.53 0.50 0.48 0.46 0.44 0.42 0.40 0.00

≤25 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 63 >63

1.00 0.89 0.83 0.78 0.74 0.69 0.66 0.63 0.60 0.57 0.54 0.52 0.50 0.48 0.46 0.45 0.43 0.42 0.40 0.00

33.4.3 Distance Component 33.4.3.1  Definition and Measurement The distance variable (D) is defined as the vertical travel distance of the hands between the origin and destination of the lift. For lifting, D can be computed by subtracting the vertical location (V) at the origin of the lift from the corresponding V at the destination of the lift (i.e., D is equal to V at the destination minus V at the origin). For a lowering task, D is equal to V at the origin minus V at the destination. 33.4.3.2  Distance Restrictions D is assumed to be at least 10 in. (25 cm) and no greater than 70 in. (175 cm). If the vertical travel distance is less than 10 in. (25 cm), then D should be set to the minimum distance of 10 in. (25 cm).

Revised NIOSH Lifting Equation    ◾    897   TABLE 33.2  Vertical Multiplier V (in.)

VM

V (cm)

VM

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 >70

0.78 0.81 0.85 0.89 0.93 0.96 1.00 0.96 0.93 0.89 0.85 0.81 0.78 0.74 0.70 0.00

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 175 >175

0.78 0.81 0.84 0.87 0.90 0.93 0.96 0.99 0.99 0.96 0.93 0.90 0.87 0.84 0.81 0.78 0.75 0.72 0.70 0.00

33.4.3.3  Distance Multiplier The distance multiplier (DM) is 0.82 + 1.8/D for D measured in inches 0.82 + 4.5/D for D measured in centimeters. For D less than 10 in. (25 cm), D is assumed to be 10 in. (25 cm) and DM = 1.0. The distance multiplier, therefore, decreases gradually with an increase in travel distance. DM = 1.0 when D is set at 10 in. (25 cm); DM = 0.85 when D = 70 in. (175 cm). Thus, DM ranges from 1.0 to 0.85 as D varies from 0 in. (0 cm) to 70 in. (175 cm). The DM value can be computed directly or determined from Table 33.3.

33.4.4 Asymmetry Component 33.4.4.1  Definition and Measurement Asymmetry refers to a lift that begins or ends outside the midsagittal plane (see Figure 33.2). In general, asymmetric lifting should be avoided. If asymmetric lifting cannot be avoided, however, the RWLs are significantly less than those limits used for ­symmetrical lifting.* An asymmetric lift may be required under the following task or workplace conditions: 1. The origin and destination of the lift are oriented at an angle to each other. 2. The lifting motion is across the body, such as occurs in swinging bags or boxes from one location to another. * It may not always be clear whether asymmetry is an intrinsic element of the task or just a personal characteristic of the worker’s lifting style. Regardless of the reason for the asymmetry, any observed asymmetric lifting should be considered an intrinsic element of the job design and should be considered in the assessment and subsequent redesign. Moreover, the design of the task should not rely on worker compliance but should rather discourage or eliminate the need for asymmetric lifting.

898    ◾    Occupational Ergonomics: Theory and Applications TABLE 33.3  Distance Multiplier D (in.)

DM

D (cm)

DM

≤10 15 20 25 30 35 40 45 50 55 60 70 >70

1.00 0.94 0.91 0.89 0.88 0.87 0.87 0.86 0.86 0.85 0.85 0.85 0.00

≤25 40 55 70 85 100 115 130 145 160 175 >175

1.00 0.93 0.90 0.88 0.87 0.87 0.86 0.86 0.85 0.85 0.85 0.00

3. The lifting is done to maintain body balance in obstructed workplaces, on rough terrain, or on littered floors. 4. Productivity standards require reduced time per lift. The asymmetric angle (A), which is depicted graphically in Figure 33.2, is operationally defined as the angle between the asymmetry line and the midsagittal line. The asymmetry line is defined as the line that joins the midpoint between the inner ankle bones and the point projected on the floor directly below the midpoint of the hand grasps, as defined by the large middle knuckle. The sagittal line is defined as the line passing through the midpoint between the inner ankle bones and lying in the midsagittal plane, as defined by the neutral body position (i.e., hands directly in front of the body, with no twisting at the legs, torso, or shoulders). Note: The asymmetry angle is not defined by foot position or the angle of torso twist, but by the location of the load relative to the worker’s midsagittal plane. In many cases of asymmetric lifting, the worker will pivot or use a step turn to complete the lift. Because this may vary significantly between workers and between lifts, we have assumed that no pivoting or stepping occurs. Although this assumption may overestimate the reduction in acceptable load weight, it will provide the greatest protection for the worker. The asymmetry angle (A) must always be measured at the origin of the lift. If significant control is required at the destination, however, then angle A should be measured at both the origin and the destination of the lift. 33.4.4.2  Asymmetry Restrictions The angle A is limited to the range 0°–135°. If A > 135°, then AM is set equal to zero, which results in an RWL of zero, or no load. 33.4.4.3  Asymmetric Multiplier The asymmetric multiplier (AM) is 1–0.0032A AM has a maximum value of 1.0 when the load is lifted directly in front of the body and decreases linearly as the angle of asymmetry

Revised NIOSH Lifting Equation    ◾    899   TABLE 33.4  Asymmetric Multiplier A(°)

AM

0 15 30 45 60 75 90 105 120 135 >135

1.00 0.95 0.90 0.86 0.81 0.76 0.71 0.66 0.62 0.57 0.00

(A) increases. The range is from a value of 0.57 at 135° of asymmetry to a value of 1.0 at 0° of asymmetry (i.e., symmetric lift). If A is greater than 135°, then AM = 0, and the load is zero. The AM value can be computed directly or determined from Table 33.4. 33.4.5 Frequency Component 33.4.5.1  Definition and Measurement The frequency multiplier is defined by (1) the number of lifts per minute (frequency), (2) the amount of time engaged in the lifting activity (duration), and (3) the vertical height of the lift from the floor. Lifting frequency (F) refers to the average number of lifts made per minute as measured over a 15 min period. Because of the potential variation in work patterns, analysts may have difficulty obtaining an accurate or representative 15 min work sample for computing F. If significant variation exists in the frequency of lifting over the course of the day, analysts should employ standard work sampling techniques to obtain a representative work sample for determining the number of lifts per minute. For those jobs where the frequency varies from session to session, each session should be analyzed separately, but the overall work pattern must still be considered. For more information, most standard industrial engineering or ergonomics texts provide guidance for establishing a representative job sampling strategy (e.g., Eastman Kodak Company [6]). 33.4.5.2  Lifting Duration Lifting duration is classified into three categories based on the pattern of continuous WT and recovery time (i.e., light work) periods. A continuous WT period is defined as a period of uninterrupted work. Recovery time (RT) is defined as the duration of light work activity following a period of continuous lifting. Examples of light work include activities such as sitting at a desk or table, monitoring operations, and light assembly work. The three categories are short duration, moderate duration, and long duration.

900    ◾    Occupational Ergonomics: Theory and Applications

Short duration: Short duration lifting tasks are those that have a work duration of 1 h or less followed by a recovery time equal to 1.0 times the WT [i.e., at least a 1.0 recovery time to work time ratio (RT/WT)].* For example, to be classified as short duration, a 45 min lifting job must be followed by at least a 45 min recovery period prior to initiating a subsequent lifting session. If the required recovery time is not met for a job of 1 h or less and a subsequent lifting session is required, then the total lifting time must be combined to correctly determine the duration category. Moreover, if the recovery period does not meet the time requirement, it is disregarded for purposes of determining the appropriate duration category. As another example, assume that a worker lifts continuously for 30 min, then performs a light work task for 10 min, and then lifts for an additional 45 min period. In this case, the recovery time between lifting sessions (10 min) is less than 1.0 times the initial 30 min WT (30 min). Thus, the two work times (30 and 45 min) must be added together to determine the duration. Since the total WT (75 min) exceeds 1 h, the job is classified as moderate duration. On the other hand, if the recovery period between lifting sessions were increased to 30 min, then the short-duration category would apply, which would result in a larger FM value. A special procedure has been developed for determining the appropriate lifting frequency (F) for certain repetitive lifting tasks in which workers do not lift continuously during the 15 min sampling period. This occurs when the work pattern is such that the worker lifts repetitively for a short time and then performs light work for a short time before starting another cycle. For work patterns such as this, F may be determined as follows, as long as the actual lifting frequency does not exceed 15 lifts/min: 1. Compute the total number of lifts performed for the 15 min period (i.e., lift rate times WT). 2. Divide the total number of lifts by 15. 3. Use the resulting value as the frequency (F) to determine the frequency multiplier (FM) from Table 33.5. For example, if the work pattern for a job consists of a series of cyclic sessions requiring 8 min of lifting followed by 7 min of light work, and the lifting rate during the work sessions is 10 lifts/min, then the frequency rate (F) that is used to determine the frequency multiplier for this job is equal to (10 × 8)/15, or 5.33 lifts/min. If the worker lifted continuously for more than 15 min, however, then the actual lifting frequency (10 lifts/min) would be used. When using this special procedure, the duration category is based on the magnitude of the recovery periods between work sessions, not within work sessions. In other words, if the work pattern is intermittent and the special procedure applies, then the intermittent recovery periods that occur during the 15 min sampling period are not considered as recovery periods for purposes of determining the duration category. For example, if the work pattern for a manual lifting job were composed of repetitive cycles consisting of 1 min of continuous lifting at a rate * Note that the required recovery time to work time ratio (RT/WT) for the short duration category was changed from 1.2 to 1.0 since publication of the original Applications Manual for the Revised NIOSH Lifting Equation (Waters et al. [1]).

Revised NIOSH Lifting Equation    ◾    901   TABLE 33.5  Frequency Multiplier (FM) Table Work Duration Frequencya Lifts/min (F) ≥0.2 0.5 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 >15 a b

≤1 h

>1 but ≤ 2 h

>2 but ≤ 8 h

V < 30

V ≥ 30

V < 30

V ≥ 30

V < 30

V ≥ 30

1.00 0.97 0.94 0.91 0.88 0.84 0.80 0.75 0.70 0.60 0.52 0.45 0.41 0.37 0.00 0.00 0.00 0.00

1.00 0.97 0.94 0.91 0.88 0.84 0.80 0.75 0.70 0.60 0.52 0.45 0.41 0.37 0.34 0.31 0.28 0.00

0.95 0.92 0.88 0.84 0.79 0.72 0.60 0.50 0.42 0.35 0.30 0.26 0.00 0.00 0.00 0.00 0.00 0.00

0.95 0.92 0.88 0.84 0.79 0.72 0.60 0.50 0.42 0.35 0.30 0.26 0.23 0.21 0.00 0.00 0.00 0.00

0.85 0.81 0.75 0.65 0.55 0.45 0.35 0.27 0.22 0.18 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

0.85 0.81 0.75 0.65 0.55 0.45 0.35 0.27 0.22 0.18 0.15 0.13 0.00 0.00 0.00 0.00 0.00 0.00

b

For lifting less frequently than once per 5 min, set F = 0.2 lift/min. V is expressed in inches as measured from the floor.

of 10 lifts/min, followed by 2 min of recovery, then the correct procedure would be to adjust the frequency according to the special procedure [i.e., F = (10 lifts/min × 5 min)/15 min = 50/15 = 3.4 lifts/min]. The 2 min recovery periods would not count toward the RT/WT ratio, however, and additional recovery periods would have to be provided as described previously. Moderate duration: Moderate duration lifting tasks are those that have a duration of more than 1 h but not more than 2 h, followed by a recovery period of at least 0.3 times the WT [i.e., at least a 0.3 recovery time to work time ratio (RT/WT)]. For example, if a worker continuously lifts for 2 h, then a recovery period of at least 36 min would be required before initiating a subsequent lifting session. If the recovery time requirement is not met and a subsequent lifting session is required, then the total work time must be added together. If the total work time exceeds 2 h, then the job must be classified as a long duration lifting task. Long duration: Long duration lifting tasks are defined as those that have a duration of 2–8 h, with standard industrial rest allowances (e.g., morning, lunch, and afternoon rest breaks). Note: No weight limits are provided for more than 8 h of work. The difference in the required RT/WT ratio for the short ( 16 in. (40 cm), height > 12 in. (30 cm), rough or slippery surfaces, sharp edges, asymmetric center of mass, unstable contents, or requires the use of gloves.   6. A worker should be able to comfortably wrap the hand around the object without causing excessive wrist deviations or awkward postures, and the grip should not require excessive force.

Definitions of the four types of manual lifting jobs are provided hereafter: 33.5.1 Single-Task Job A manual lifting job is defined as a single-task job if the task variables do not differ from task to task or if only one task is of interest (e.g., single most stressful task). This may be the case if one of the tasks clearly has a dominant effect on strength demands, localized muscle fatigue, or whole body fatigue. 33.5.2 Multitask Job A manual lifting job is defined as a multitask job if there are a distinct set of defined lifting tasks with a fixed set of task characteristics, but the task characteristics differ significantly between tasks. An example of a multitask job is a palletizing job in which each layer of the pallet can be treated as a unique set of lifts with fixed task characteristics. A multitask analysis is more difficult to perform than a single-task analysis because additional data and computations are required. The multitask approach, however, will provide more detailed information about specific strength and physiological demands.

904    ◾    Occupational Ergonomics: Theory and Applications Object lifted Container

Loose object

Optimal container?

Yes

No

Bulky object?

Yes

No Poor

Optimal handles? Yes

No

No

Optimal grip? Yes

No

Fingers flexed 90 degrees? Yes Fair

Good

FIGURE 33.3  Decision tree for coupling quality. TABLE 33.7  Coupling Multiplier Coupling Multiplier Coupling Type Good Fair Poor

V < 30 in. (75 cm)

V ≥ 30 in. (75 cm)

1.00 0.95 0.90

1.00 1.00 0.90

33.5.3 Sequential Lifting Job Recently, NIOSH researchers developed the sequential lifting index (SLI), a new method for using the RNLE to assess jobs in which workers rotate between work stations [7]. When workers rotate between workstations and perform different lifting tasks at each work station, the SLI should provide a useful metric for determining which tasks and rotation slots are having the most effect on the physical demand for the job. 33.5.4 Variable Lifting Job A team of researchers also recently developed the variable lifting index (VLI), a new method for using the RNLE to assess jobs in which the task characteristics frequently vary between lifts, such as might be seen in a warehouse or distribution center [8]. The VLI approach is similar to the CLI described previously, but for the VLI, the task characteristics can vary from lift to lift, whereas the CLI is restricted to a small set of defined task conditions.

Revised NIOSH Lifting Equation    ◾    905  

For many lifting jobs, it may be acceptable to use any of the four approaches (i.e., either the single-task, multitask, sequential, or variable approach). The analyst should choose the method most appropriate for the job, keeping in mind that each type of analysis requires different amounts of data collection. The single-task analysis is the easiest to use, but when a job consists of more than one task and detailed information is needed to specify engineering modifications, then the more advanced procedures (multitask, sequential, or variable methods) provide a reasonable method of assessing the overall physical demands may be needed. The more advanced procedures are more complicated to use than the single-task procedure and require a greater understanding of assessment terminology and mathematical concepts. Therefore, the decision to use one of the approaches should be based on (1) the need for detailed information about all facets of the multitask lifting job, (2) the need for accuracy and completeness of data regarding assessment of the physiological demands of the task, and (3) the analyst’s level of understanding of the assessment procedures. The decision about whether control is required at the destination of the lift or not is important because the physical demands on the worker may be greater at the destination of the lift than at the origin, especially when significant control is required. When significant control is required at the destination, the physical stress is increased because the load will have to be accelerated upward to slow its descent. This acceleration may be as great as the acceleration at the origin of the lift and may create high loads on the spine. Therefore, if significant control is required, then the RWL and LI should be determined at both locations and the lower of the two values used to specify the overall level of physical demand. To perform a lifting analysis using the RNLE, two steps are taken: (1) data are collected at the worksite as described in step 1 hereafter, and (2) the RWL and LI values (LI, CLI, SLI, or VLI) are computed using one of the four analysis procedures described in step 2 as follows. Step 1: Collect data The relevant task variables must be carefully measured and clearly recorded in a concise format. As mentioned previously, these variables include the horizontal location of the hands (H), vertical location of the hands, (V), vertical displacement (D), asymmetric angle (A), lifting frequency (F), and coupling quality (C). A job analysis worksheet, as shown in Figure 33.4 for single-task jobs or Figure 33.5 for multitask jobs, provides a simple form for recording the task variables and the data needed to calculate the RWL and LI values. A thorough job analysis is required to identify and catalog each independent lifting task in the worker’s complete job. For multitask jobs, data must be collected for each task. Step 2: Calculate the LI, CLI, SLI, or VLI for the job 33.5.4.1  Lifting Index for Single-Task Jobs For a single-task procedure, step 2 consists of computing the RWL and the LI. This is accomplished as follows. Calculate the RWL at the origin for each lift. For lifting tasks that require significant control at the destination, calculate the RWL at both the origin and the destination of the lift. The latter procedure is required if (1) the worker has to regrasp the load near the

906    ◾    Occupational Ergonomics: Theory and Applications JOB ANALYSIS WORKSHEET DEPARTMENT JOB TITLE ANALYST’S NAME DATE

JOB DESCRIPTION

STEP 1. Measure and record task variables Object Weight (lb) L (AVG.)

L (Max.)

Vertical Hand Location (in.) Asymmetric Angle (degrees) Frequency Rate Duration Object Coupling Origin Destination Distance (in.) Origin Destination lifts/min (h) H V H V D A A F C

STEP 2. Determine the multipliers and compute the RWL’s RWL = LC

HM

VM

DM

AM

FM

CM

ORIGIN

RWL = 51

=

lb

DESTINATION

RWL = 51

=

lb

STEP 3. Compute the LIFTING INDEX ORIGIN

LIFTING INDEX =

DESTINATION

LIFTING INDEX =

OBJECT WEIGHT (L) RWL OBJECT WEIGHT (L) RWL

=

=

=

=

FIGURE 33.4  Single-task job analysis worksheet.

destination of the lift, (2) the worker has to momentarily hold the object at the destination, or (3) the worker has to position or guide the load at the destination. The purpose of calculating the RWL at both the origin and destination of the lift is to identify the most stressful location of the lift. Therefore, the lower of the two RWL values should be used to compute LI for the task, as this value would represent the limiting set of conditions. The assessment is completed on the single-task worksheet by determining the LI for the task of interest. This is accomplished by comparing the actual weight of the load (L) lifted with the RWL value obtained from the lifting equation. 33.5.4.2  Composite Lifting Index for Multitask Jobs For a multitask procedure, step 2 comprises three substeps:

1. Compute the frequency-independent recommended weight limit (FIRWL) and single-task recommended weight limit (STRWL) for each task. 2. Compute the frequency-independent lifting index (FILI) and single-task lifting index (STLI) for each task. 3. Compute the composite lifting index (CLI) for the overall job. Compute the frequency-independent recommended weight limits (FIRWLs): Compute the FIRWL value for each task by using the respective task variables and setting the

Revised NIOSH Lifting Equation    ◾    907   MULTI-TASK JOB ANALYSIS WORKSHEET DEPARTMENT JOB TITLE ANALYST’S NAME DATE

JOB DESCRIPTION

STEP 1. Measure and Record Task Variable Data Hand Location (in.) Object Vertical Asymmetry Angle (degrees) Task No. Weight (lb) Origin Destination Distance (in.) Origin Destination L (Avg.) L (Max.)

H

V

H

V

D

A

A

Frequency Rate lifts/min F

Duration (h)

Coupling C

STEP 2. Compute multipliers and FIRWL, STRWL, FILI, and STLI for Each Task Task FILI = STLI = New FIRWL × FM STRWL L/FIRWL L/STRWL Task No. No. LC × HM × VM × DM × AM × CM 51

F

51 51 51 51 STEP 3. Compute the Composite Lifting Index for the Job (After renumbering tasks) CLI = STLI1 + + + + FILI3 FILI4 FILI2 FILI2(1\FM1,2 – 1\FM1) FILI2(1\FM1,2,3 – 1\FM1,2)

FILI2(1\FM1,2,3,4 – 1\FM1,2,3)

FILI5 FILI2(1\FM1,2,3,4,5 – 1\FM1,2,3,4)

CLI =

FIGURE 33.5  Multitask job analysis worksheet.

frequency multiplier (FM) to a value of 1.0. The FIRWL for each task reflects the compressive force and muscle strength demands for a single performance of that task. If significant control is required at the destination for any individual task, the FIRWL must be computed at both the origin and the destination of the lift, as described earlier for a single-task analysis. Compute the single-task recommended weight limit (STRWL): Compute the STRWL for each task by multiplying its FIRWL by the appropriate FM. The STRWL for a task reflects the overall demands of that task, assuming it was the only task being performed. Note: This value does not reflect the overall demands of the task when the other tasks are considered. Nevertheless, it is helpful in determining the extent of excessive physical stress for an individual task. Compute the frequency-independent lifting index (FILI): The FILI is computed for each task by dividing the maximum load weight (L) for that task by the respective FIRWL. The maximum weight is used to compute the FILI because the maximum weight determines the maximum biomechanical loads to which the body will be exposed, regardless of the frequency of occurrence. Thus, the FILI can identify individual tasks with potential strength problems for infrequent lifts. If any of the FILI values exceeds a value of 1.0, then job design changes may be needed to decrease the strength demands.

908    ◾    Occupational Ergonomics: Theory and Applications

Compute the single-task lifting index (STLI): The STLI is computed for each task by dividing the average load weight (L) for that task by the respective STRWL. The average weight is used to compute the STLI because the average weight provides a better representation of the metabolic demands, which are distributed across the tasks rather than being dependent on individual tasks. The STLI can be used to identify individual tasks with excessive physical demands (i.e., tasks that would result in fatigue). The STLI values do not indicate the relative stress of the individual tasks in the context of the whole job, but they can be used to prioritize the individual tasks according to the magnitude of their physical stress. Thus, if any of the STLI values exceeds a value of 1.0, then ergonomic changes may be needed to decrease the overall physical demands of the task. Note: It may be possible to have a job in which all of the individual tasks have an STLI less than 1.0 and yet is physically demanding due to the combined demands of the tasks. In cases where the FILI exceeds the STLI for any task, the maximum weights may represent a significant problem, and careful evaluation is necessary. Compute the composite lifting index (CLI): The assessment is completed on the multitask worksheet by determining the CLI for the overall job. The CLI is computed as follows: 1. The tasks are renumbered in order of decreasing physical stress, from the task with the greatest STLI down to the task with the smallest STLI. The tasks are renumbered in this way so that the more difficult tasks are considered first. 2. The CLI for the job is then computed according to the formula

∑ ΔLI

CLI = STLI1 +

where ⎛

1

∑ ΔLI = FILI × ⎜⎝ FM 2



1,2

−

⎛ 1 1 ⎞ ⎡ 1 ⎞⎤ + ⎢FILI3 × ⎜ − ⎥ ⎟ FM1 ⎠ ⎣ ⎝ FM1,2,3 FM1,2 ⎟⎠ ⎦

⎡ ⎛ ⎞⎤ ⎛ 1 1 1 ⎞⎤ … ⎡ 1 − + ⎢FILI × ⎜ − ⎥ ⎥ + + ⎢FILIn × ⎜ ⎟ ⎝ FM1,2,3, 4 FM1,2,3 ⎠ ⎦ ⎝ FM1,2,3, 4,…,n FM1,2,3,…,(n −1) ⎟⎠ ⎥⎦ ⎢⎣ ⎣

Note: (1) The numbers in the subscripts refer to the new task numbers and (2) the FM values are determined from Table 33.5, based on the sum of the frequencies for the tasks listed in the subscripts. An example: The following example is provided to demonstrate this step of the multitask procedure. Assume that an analysis of a typical three-task job provided the results shown in Table 33.8. To compute the CLI for this job, the tasks are renumbered in order of decreasing physical stress, beginning with the task with the greatest STLI. In this case, as shown in Table 33.8,

Revised NIOSH Lifting Equation    ◾    909   TABLE 33.8  Computations from Multitask Example Task No. 1 2 3

Load Weight (L)

Task Frequency (F)

FIRWL

FM

STRWL

FILI

STLI

New Task No.

30 20 10

1 2 4

20 20 15

0.94 0.91 0.84

18.8 18.2 12.6

1.5 1.0 0.67

1.6 1.1 0.8

1 2 3

2H A

A MMH

1H

1H

B

R LUNCH

2H A

A MMH

1H

2H

B

C C RECOV

CASE 1—Sequence AABC. Assuming each letter represents 1 h, the SLI for this job would be calculated as follows: FM LC × HM × VM × DM F Lifts/ Load Actual Task × AM × CM min FIRWL Wt Duration A B

23 × 0.83 × 0.78 × 0.88 × 0.80 × 0.90 23 × 1.00 × 0.93 × 0.93 × 0.88 × 0.90

LI

FM Total Duration LImax TF

Order by LImax

8

9.43

10

0.35

3.03

0.18

5.89

0.46

1

4

15.76

15

0.84

1.13

0.45

2.11

0.23

2

CASE 2—Sequence ACBB. The SLI would be calculated as follows: Task A B

FM LC × HM × VM × DM F Lifts/ Load Actual × AM × CM min FIRWL Wt Duration 23 × 0.83 × 0.78 × 0.88 × 0.80 × 0.90 23 × 1.00 × 0.93 × 0.93 × 0.88 × 0.90

LI

Order FM Total by Duration LImax TF LImax

8

9.43

10

0.60

1.77

0.35

3.03

0.23

1

4

15.76

15

0.72

1.32

0.72

1.32

0.46

2

CASE 3—Sequence AABB. The SLI would be calculated as follows: Task A B

FM LC × HM × VM × DM F Lifts/ Load Actual × AM × CM min FIRWL Wt Duration 23 × 0.83 × 0.78 × 0.88 × 0.80 × 0.90 23 × 1.00 × 0.93 × 0.93 × 0.88 × 0.90

LI

Order FM Total by Duration LImax TF LImax

8

9.43

10

0.35

3.03

0.18

5.89

0.46

1

4

15.76

15

0.72

1.32

0.45

2.11

0.46

2

the task numbers do not change. Next, the CLI is computed according to the formula given earlier. The task with the greatest CLI is Task 1 (STLI = 1.6). The sum of the frequencies for Tasks 1 and 2 is 1 + 2, or 3, and the sum of the frequencies for Tasks 1, 2, and 3 is 1 + 2 + 4, or 7. Then, from Table 33.5, FM1 = 0.94, FM1,2 = 0.88, and FM1,2,3 = 0.70. Finally,

CLI = 1.6 + 1.0(1/0.88 − 1/0.94) + 0.67(1/0.70) − 1 / 0.88 = 1.6 + 0.7 + 0.20 = 1.9

910    ◾    Occupational Ergonomics: Theory and Applications

Note that the FM values were based on the sum of the frequencies for the subscripts, the vertical height, and the duration of lifting. 33.5.4.3  Sequential Lifting Index An example of a sequential lifting job would be one in which a worker lifts one product at the end of an assembly line for a fixed period of time (e.g., 1 h), and then changes products for a fixed period of time, and so on. Another example of a sequential lifting job would be one in which a worker performs a series of lifts at one workstation (e.g., a palletizing job) and then rotates to another workstation and performs a different set of lifting tasks (e.g., a different palletizing job). In such situations, the existing LI and CLI calculations cannot be used to estimate the physical demand of the job. For these types of jobs, each rotation position will be considered to be a job element.

The following steps are required to calculate the SLI for a job: 1. The work pattern or rotation pattern should be documented on a timeline of the shift, as shown in the following example. The pattern should show how the worker rotates among the different work stations or tasks. In the following example, A and B are manual lifting tasks, R represents a work break for lunch, and C represents a light duty task (i.e., a task without lifting). 2. When using this method, you must assume that no manual handling task (single or multiple) can last more than 4 h continuously without a recovery period (such as light duty or lunch). In cases where the total work time exceeds 8 h, you can calculate the SLI value for each 4 h period and then take the larger of the values to represent the SLI for the job as a whole. 3. Calculate the LI or CLI for each unique task category, as described by Waters et al. [2]. When a single task is performed for more than one continuous hour, the LI value for that task must be calculated using the duration category for that period, but when two identical tasks are separated by another task, then each category is calculated using its own duration. Considering the preceding example, if the order is ABAB, then the LI for each letter would be calculated using the short duration (1 h category) frequency multiplier (FM). If the sequence was AABB, however, then the FM for each would be calculated using the moderate duration (1–2 h category) FM. Similarly, for the sequence AAAB, the FM for each would be calculated using the long duration (8 h category). 4. For each task category, calculate the maximum lifting index (LImax), by taking the frequency multiplier as being relevant to task frequency related to the overall duration obtained by adding together the single-task duration times. For example, in the aforementioned sequences, the LImax for each task would be calculated using the long duration category since the total continuous work time exceeds the 2 h category. Once the LImax values are calculated for each task category, the tasks should be reordered from highest to lowest.

Revised NIOSH Lifting Equation    ◾    911  

5. Calculate the time fraction (TF) for each task category by dividing the task duration in minutes by 240 min (e.g., for AABC, the TFA = 120/240 = 0.50 and TFB = 60/240 = 0.25). 6. Following the reordering of tasks, as already noted, determine the LI value for the new Task 1 (i.e., the task with the largest LImax) using its actual task duration. This is calculated by dividing the load weight of the task by the product of the FIRWL and the actual task duration FM value for that task. This value is then set equal to LI1. For example, assume that a job consists of two tasks and the task with the largest LImax has an LImax of 3.2, an FIRWL of 12.0 lb, a load weight of 18.0 lb, and an actual FM value of 0.6; the LI for this task would be 18.0/12.0 × 0.6 or 2.5. In this case, LI1 would be set equal to 2.5.

7. Calculate the SLI using the following formula: SLI = LI1 + (LImax − LI1) × K



LImax1 × TF1 + LImax2 × TF2 + … + LImaxn × TFn ∑ where K = LImax1

Please note that 1. LImax1 is the highest LImax, and LI1 is its corresponding LI. It may be that LI1 is not the highest in absolute terms, but this does not bias the calculations that follow. 2. The time fraction (TF) is calculated on 240 min because in most actual working environments no continuous lifting task usually take place for periods longer than 4 h. Moreover, the use of 240 min as denominator in the calculation of TF enables a better evaluation of the SLI. 3. K is a weighting factor calculated by multiplying the LImax of each task by the corresponding TF, adding together the resulting values and then dividing them by the LImax1. 4. If the work pattern for an overall job is such that there are sufficient recovery periods to insure that the job always stays in the short duration category (i.e., sufficient recovery means that the duration of any task category is 1 h or less followed by a recovery period of equal duration), then the SLI is equal to the greatest of all LImax or CLImax. In this special case, the LImax1 becomes LI1, which cancels out the term (LImax1-LI) in the formula. Therefore, the SLI is equal to LI1. Since the LI1 is set to be the greatest LI among all tasks, the SLI for this job would be set to the greatest of the LI values for all the tasks. For example, if the job rotation is something like ACBC, from the previous example, where C is a sufficient recovery period for tasks A and B, then the LI for the job would be either the LI for Task A or Task B, whichever is greatest.

912    ◾    Occupational Ergonomics: Theory and Applications

Example Assume a job consists of sequential Tasks A and B, and a recovery or light duty Task C. The SLI is calculated for various sequences shown hereafter. Case 1—Sequence AABC. Assuming each letter represents 1 h, the SLI for this job would be calculated as follows: SLI = LI1 + ((LImax1 − LI1) × K SLI = LI1 + (LImax1 − LI1) ×

5.89 × 0.46 + 2.11 × 0.23 5.89

SLI = 3.03 + (5.89 − 3.03) ×

LImax1 × TF1 + LImax2 × TF2 LImax1

SLI = 4.58

Case 2—Sequence ACBB. The SLI would be calculated as follows: SLI = LI1 + ((LImax1 − LI1) × K SLI = LI1 + (LImax1 − LI1) × SLI = 1.77 + (5.89 − 1.77) ×

LImax1 × TF1 + LImax2 × TF2 LImax1

5.89 × 0.23 + 2.11 × 0.46 5.89

SLI = 3.40

Case 3—Sequence AABB. The SLI would be calculated as follows: SLI = LI1 + ((LImax1 − LI1) × K SLI = LI1 + (LImax1 − LI1) × SLI = 3.03 + (5.89 − 3.03) ×

LImax1 × TF1 + LImax2 × TF2 LImax1

5.89 × 0.46 + 2.11 × 0.46 5.89

SLI = 4.82

Remember, that when a task is performed for more than 1 h, the FM value for the actual time period is used. That is, when AA was performed in the Case 1 mentioned earlier, the FMactual was 0.35, whereas in the Case 2 it was 0.6. Similarly, in Case 1, the FMactual for B was 0.91, whereas for Case 2 it was 0.84. Based on our assessment of the

Revised NIOSH Lifting Equation    ◾    913  

SLI response across different sequence patterns, it appears to be sensitive to variations in the sequence of tasks across the work shift. 33.5.4.4  Variable Lifting Index The VLI, which is equivalent to the LI, CLI, or SLI for single-lifting, multi-lifting, or sequential lifting jobs, is computed using “probability data” collected at the worksite as input into the VLI equation. The input data for the VLI calculation will be obtained at the worksite through adjustable sampling methods of actual jobs, use of historical computerized production data obtained from the employer, when available, or some combination of the two sources of data. The sampling methods will be adjusted based upon the amount of variability observed in the task characteristics, such as the weight of load lifted, horizontal distance, asymmetry, etc. The greater the variability between lifts, the greater will be the requirement for data sampling. The concept for the method is similar to the CLI method for multitask jobs. The difference is that rather than using individual task elements, all of the lifts will be distributed into a fixed number of FILI categories (one to nine categories), each with a variable frequency. These six FILI categories will then be weighted using the CLI equation. The frequency multiplier for each category is based on the average overall frequency for the six individual LI categories. The VLI should provide a reasonable estimate of the physical demand of the job that can be used to determine if the task is acceptable or not and how changes in the mix of tasks might affect the overall physical demand of the job. The steps are as follows:

1. Determine the range of FILI values for all of the sampled lifts. 2. Divide the range of FILI values into six categories, taking into account the variability of obtained results. 3. Determine the frequency of lifts in each of the six categories. 4. Apply the VLI using the CLI equation, but use the frequency data for each LI category to calculate the appropriate FM values for the calculation. The VLI is computed as follows: 1. The task categories are renumbered in order of decreasing physical stress, beginning with the task category with the greatest single-task lifting index (STLI) down to the task category with the smallest STLI. The STLI is the defined as the LI value for each task, independent of the other tasks. The task categories are renumbered in this way so that the more difficult task categories are considered first. 2. The VLI for the job is then computed according to the following formula:

VLI = STLI1 + ∑ ΔLI

914    ◾    Occupational Ergonomics: Theory and Applications

where ⎛ 1 ⎞⎞ ⎛ 1 ∑ ΔLI = ⎜ FILI 2 × ⎜ − ⎝ FM1,2 FM1 ⎟⎠ ⎟⎠ ⎝ ⎛ 1 ⎛ 1 + ⎜ FILI 3 × ⎜ − ⎝ FM1,2,3 FM1,2 ⎝

⎞⎞ ⎟⎠ ⎟ ⎠

⎛ 1 1 ⎛ + ⎜ FILI 4 × ⎜ − ⎝ FM1,2,3,4 FM1,2,3 ⎝

⎞⎞ ⎟⎠ ⎟ ⎠

 ⎛ 1 1 ⎛ + ⎜ FILIn × − ⎜⎝ FM1,2,3,4,...,n FM1,2,3,...,(n-1) ⎝



⎞⎞ ⎟⎠ ⎟ ⎠

Note that (1) the numbers in the subscripts refer to the new task category numbers, and (2)  the FM values are determined from the frequency table published in the applications manual (Waters et al. [2]). The appropriate FM values are based on the sum of the frequencies for the task categories listed in the subscripts. Example A hypothetical example will demonstrate how the VLI equation might be applied. Assume that job sampling at a manufacturing plant revealed that the largest FILI sampled for any individual lift was 2.8. According to the VLI procedure, the range of FILI categories should be evaluated and a set of FILI categories should be chosen. For this example, six FILI categories were chosen and were defined as: 0–0.45, 0.46–0.61, 0.62–0.99, 1.0–1.51, 1.52–2.02, and 2.03–2.8. The choice of FILI categories is somewhat arbitrary, but we suggest choosing six categories. Also, assume that analysis of the sampled data revealed that the average FILI for individual lifts in each of these six categories and the percentage of tasks falling into the six cells are as shown in Table 33.9. As with the SLI approach, the VLI approach works best if the job is performed for a full 8 h shift [7]. If the overall frequency of lifting across an 8 h shift is 4/min, then the frequency of lifts for each category can be calculated (see Table 33.9). TABLE 33.9  Hypothetical Data for VLI Example LI Categories Category Data Representative FILI within category Renumbered Percentage of tasks Frequency (lifts/min)

0–0.45

0.46–0.61

0.62–0.99

1.0–1.51

1.52–2.02

2.03–2.8

0.33

0.53

0.79

1.20

1.66

2.8

6 10% 0.5

5 15% 0.9

4 25% 1.1

3 25% 0.9

2 15% 0.4

1 10% 0.2

Revised NIOSH Lifting Equation    ◾    915  

Based on the hypothetical data presented, the VLI for this job can be calculated, as follows:

VLI = STLI1 + ∑ ΔLI



STLI1 = 3.32



ΔFILI2 = 1.66((1/.80) − (1/.85)) = .116



ΔFILI3 = 1.2((1/.70) − (1/.80)) = .204



ΔFILI 4 = .79((1 /.60) − (1 /.70)) = .205



ΔFILI5 = .53((1/.50) − (1/.60)) = .159



ΔFILI6 = .33((1/.46) − (1/.50)) = .069



VLI = STLI1 + ΔFILI2 + ΔFILI3 + ΔFILI4 + ΔFILI5 + ΔFILI6



= 3.32 + .116 + .204 + .205 + .159 + .069 = 4.07

33.6 APPLYING THE EQUATIONS 33.6.1 Using RWL and LI, CLI, SLI, and VLI to Guide Ergonomic Design The RWL and LI values (LI, CLI, SLI, or VLI) can be used to guide ergonomic design in several ways. 1. The individual multipliers can be used to identify specific job-related problems. The relative magnitude of each multiplier indicates the relative contribution of each task factor (e.g., horizontal, vertical, frequency). 2. The RWL can be used to guide the redesign of existing manual lifting jobs or to design new manual lifting jobs. For example, if the task variables are fixed, then the maximum weight of the load could be selected so as not to exceed the RWL; if the weight is fixed, then the task variables could be optimized so as not to exceed the RWL. 3. The LI values can be used to estimate the relative magnitude of physical stress for a task or job. The greater the LI value, the smaller the fraction of workers capable of safely sustaining the level of activity. Thus, two or more job designs could be compared. 4. The LI values can be used to prioritize ergonomic redesign. For example, a series of suspected hazardous jobs could be rank ordered according to LI values, and a control strategy could be developed according to the rank ordering (i.e., jobs with lifting indices above 1.0 or higher would benefit the most from redesign).

916    ◾    Occupational Ergonomics: Theory and Applications

33.6.2 Rationale and Limitations for Lifting Index Values (LI, CLI, SLI, and VLI) The NIOSH RWL equation and LI are based on the concept that the risk of lifting-related LBP increases as the demands of the lifting task increase. In other words, as the magnitude of the LI increases, (1) the level of the risk for a given worker would be increased and (2) a greater percentage of the workforce is likely to be at risk for developing lifting-related LBP. The shape of the risk function, however, is not known. Without additional data showing the relationship between LBP and LI, it is impossible to predict the magnitude of the risk for a given individual or the exact percent of the work population who would be at an elevated risk for LBP. To gain a better understanding of the rationale for the development of the RWL and LI, consult [1], which provides a discussion of the criteria underlying the lifting equation and of the individual multipliers. It also identifies both the assumptions and uncertainties in the scientific studies that associate manual lifting and low back injuries. 33.6.3 Job-Related Intervention Strategy The LI may be used to identify potentially hazardous lifting jobs or to compare the relative severity of two jobs for the purpose of evaluating and redesigning them. From the NIOSH perspective, it is likely that lifting tasks with LI > 1.0 pose an increased risk for liftingrelated LBP for some fraction of the workforce [1]. Hence, to the extent possible, lifting jobs should be designed to achieve an LI of 1.0 or less. Some experts believe, however, that worker selection criteria can be used to identify workers who can perform potentially stressful lifting tasks (i.e., lifting tasks that would exceed an LI of 1.0) without significantly increasing their risk of work-related injury above the baseline level [9,10]. Those who endorse the use of selection criteria believe that the criteria must be based on research studies, empirical observations, or theoretical considerations that include job-related strength testing and/or aerobic capacity testing. Even these experts agree, however, that many workers will be at a significant risk of a work-related injury when performing highly stressful lifting tasks (i.e., lifting tasks with LI > 3.0). Also, “informal” or “natural” selection of workers may occur in many jobs that require repetitive lifting tasks. According to some experts, this may result in a unique workforce that may be able to work above a LI of 1.0, at least in theory, without substantially increasing their risk of low back injuries above the baseline rate of injury. 33.6.4 Example Problems Two simple example problems are provided to demonstrate the proper application of the lifting equation and procedures.* The procedures provide a method for determining the level of physical stress associated with a specific set of lifting conditions and assist in identifying the contribution of each job-related factor. The examples also provide guidance in developing an ergonomic redesign strategy. Specifically, for each example, a job description, job analysis, hazard assessment, redesign suggestion, illustration, and completed worksheet are provided. * Additional example problems can be reviewed in Applications Manual for the RNLE [2].

Revised NIOSH Lifting Equation    ◾    917  

To help clarify the discussion of the example problems, and to provide a useful reference for determining the multiplier values, the six multipliers used in the example problems are derived from the data contained in Tables 33.1 through 33.7. A series of general design/redesign suggestions for each job-related risk factor are provided in Table 33.9. These suggestions can be used to develop a practical ergonomic design/ redesign strategy. Example 1: Loading Supply Rolls Job description: With both hands directly in front of the body, a worker lifts the core of a 35 lb roll of paper from a cart and then shifts the roll in the hands and holds it by the sides to position it on a machine, as shown in Figure 33.6. Significant control of the roll is required at the destination of the lift. Also, the worker must crouch at the destination of the lift to support the roll in front of the body but does not have to twist. Job analysis: The task variable data are measured and recorded on the job analysis worksheet (Figure 33.7). The vertical location of the hands is 27 in. at the origin and 10 in. at the destination. The horizontal location of the hands is 15 in. at the origin and 20 in. at the destination. The asymmetric angle is 0° at both the origin and the destination, and the frequency is 4 lifts/shift (i.e., less than 0.2 lift/min for less than 1 h; see Table 33.5). Using Table 33.6, the coupling is classified as poor because the worker must reposition the hands at the destination of the lift and cannot flex the fingers to the desired 90° angle (e.g., hook grip). No asymmetric lifting is involved (i.e., A = 0), and significant control of the object is required at the destination of the lift. Thus, RWL should be computed at both the origin and the destination of the lift. The multipliers are computed from the lifting equation or determined from the multiplier tables (Tables 33.1 through 33.5 and 33.7). As shown in Figure 33.7, for this activity RWL = 28.0 at the origin and RWL = 18.1 lb at the destination. Hazard assessment: The weight to be lifted (35 lb) is greater than the RWL at both the origin and destination of the lift (28.0 and 18.1 lb, respectively). At the origin, LI = 35 lb/28.0 lb = 1.3; and at the destination, LI = 35 lb/18.1 lb = 1.9. These values indicate that this job is only slightly stressful at the origin but moderately stressful at the destination of the lift.

36 lb 27 in.

10 in. 20 in.

FIGURE 33.6  Loading supply rolls, Example 1.

15 in.

918    ◾    Occupational Ergonomics: Theory and Applications

Shipping DEPARTMENT Packager JOB TITLE ANALYST’S NAME DATE

JOB ANALYSIS WORKSHEET JOB DESCRIPTION Loading paper supply rolls Example 2

STEP 1. Measure and record task variables Object Weight (lb) L (AVG.) L (Max.) 35

35

Hand Location (in.) Asymmetric Angle (degrees) Frequency Rate Duration Object Vertical Coupling Origin Destination Distance (in.) Origin Destination lifts/min (h) H V H V D A A F C 15

27

20

10

17

0

0

< .2

3000 tubs in 2002; 3400 in 2003). The only incentive for adoption was improved working conditions [33].

REFERENCES 1. National Institute for Occupational Safety and Health. Research to Practice at NIOSH. http://www.cdc.gov/niosh/r2p (accessed October 6, 2009), 2009. 2. J. Howard. Informing public health policy and practice: The strategic management of research processes and organizations. Governance: An International Journal of Policy, Administration, and Institutions 22(2): 203–216 (2009). 3. Canadian Institutes of Health Research. Knowledge Translation Strategy 2005–2009: Innovation in Action. http://www.cihr-irsc.gc.ca/e/26574.html#blueprint (accessed October 6, 2009), 2009. 4. National Institutes of Health. Re-engineering the Clinical Research Enterprise: Translational Research. http://commonfund.nih.gov/aboutroadmap.aspx (accessed October 6, 2009), 2011. 5. S.H. Woolf. The meaning of translational research and why it matters. JAMA 299: 211–213 (2008). 6. The Ohio State University Medical Center. Translational Research. http://medicalcenter.osu. edu/research/translational_research/Pages/index.aspx (accessed October 6, 2009), 2009. 7. Centers for Disease Control and Prevention. CDC Partnership Tool Kit, Draft Version 1.1. http://intranet.cdc.gov/nchm/dpsa/ptk/full_version.pdf (accessed November 8, 2009), 2006. 8. K. Schmeer. Guidelines for Conducting a Stakeholder Analysis. Partnerships for Health Reform, ABT Associates, Inc., Bethesda, MD, 1999. 9. Employers’ Organisation. Making the Most of Partnership Working. http://www.lgpartnerships. com/ (accessed November 8, 2009). 10. D. Michaels and W. Wagner. Disclosure in regulatory science. Science 302: 2073 (2003). 11. National Institutes of Health. Developing sponsored research agreements: Considerations for recipients of NIH research grants and contracts, NIH Guide for Grants and Contracts 23(25). http://grants.nih.gov/grants/guide/notice-files/not94-213.html (accessed October 6, 2009), July 1, 1994. 12. Bureau of Labor Statistics. Incidence Rates for Nonfatal Occupational Injuries and Illnesses Involving Days Away from Work Per 10,000 Full-Time Workers by Industry and Selected Events Or Exposures Leading to Injury Or Illness. http://www.bls.gov/data/home.htm (accessed October 8, 2009), 2006. 13. T. Waters, V. Putz-Anderson, A. Garg et al. Revised NIOSH equation for the design and evaluation of manual lifting tasks. Ergonomics 36: 749–776 (1993). 14. M. Siegel and L. Doner. Marketing Public Health: Strategies to Promote Social Change, Aspen Publishers, Gaithersburg, MD, 1998. 15. E. Rogers. Diffusion of Innovations. Free Press, New York, 2003. 16. P. Kotler, N. Roberto, and N. Lee. Social Marketing: Improving the Quality of Life. SAGE Publications, Thousand Oaks, CA, 2002. 17. W. Smith and J. Strand. Social Marketing Behavior: Practical Resources for Social Change Professionals. Academy for Educational Development, Washington, D.C., 2008.

1086    ◾    Occupational Ergonomics: Theory and Applications 18. Canadian Population Health Initiative. An Environmental Scan of Research Transfer Strategies. http://secure.cihi.ca/cihiweb/products/EnviroScan.pdf (accessed January 30, 2011), 2001. 19. K. Graham and J. Logan. Using the Ottawa model of research use to implement a skin care program. Journal of Nursing Care Quality, 19: 18–24 (2004). 20. National Institute for Occupational Safety and Health. Safe Patient Handling Training for Schools of Nursing. http://www.cdc.gov/niosh/docs/2009-127/ (accessed January 31, 2011), 2009. 21. I. Ajzen. From intentions to actions: A theory of planned behavior, in Action-Control: From Cognition to Behavior. J. Kuhl and J. Beckmann, (eds.), Springer, Heidelberg, Germany, 1985. 22. N.N. Menzel, N.L. Hughes, T. Waters, L. Shores, and A. Nelson. Preventing musculoskeletal disorders in nurses: A safe patient handling curriculum module for nursing schools. Nursing Educator 3: 130–135 (2007). 23. A.L. Nelson, T.R. Waters, N.N. Menzel et al. Effectiveness of an evidence-based curriculum module in nursing schools targeting safe patient handling and movement. International Journal of Nursing Education Scholarship 4: 1–19 (2007). 24. Federal Laboratory Consortium for Technology Transfer. FLC Technology Transfer Desk Reference, 2006. http://www.federallabs.org/pdf/T2_Desk_Reference.pdf (accessed October 1, 2009), 2006. 25. D. Lancaster. When to patent, Midnight Engineering. http://www.tinaja.com/glib/when2pat.pdf (accessed November 8, 2009), 1994. 26. Centers for Disease Control and Prevention. Technology Transfer. http://www.cdc.gov/osels/ laboratory_science/tech_tran/index.htm (accessed February 15, 2011), 2010. 27. U.S. Patent and Trademark Office. General Information Regarding Patents. http://www.uspto. gov/patents/basics/index.html (accessed October 19, 2009), 2005. 28. D.M. Anderson. Commercialization. http://www.halfcostproducts.com/commercialization. htm (accessed February 15, 2011), 2010. 29. R. Vaughan. Evaluation and public health. American Journal of Public Health 93(3): 360 (2004). 30. Centers for Disease Control and Prevention. Framework for program evaluation in public health. MMWR Recommendations and Reports 48(RR11): 1–40 (1999). 31. Institute of Medicine and National Research Council. Committee on the Review of NIOSH Research Programs. Evaluating Occupational Health and Safety Research Programs: Framework and Next Steps. http://www.nap.edu/catalog/12639.html (accessed November 16, 2009), 2009. 32. National Institute for Occupational Safety and Health. Vineyard Harvest Ergonomics Intervention Partnership. http://www.cdc.gov/niosh/pgms/commpart/vinyard.html (accessed February 10, 2011), 2003. 33. J.A. Miles, F.A. Fathallah, J. Faucett, J.M. Meyers, and I. Janowitz. Ergonomic Evaluation of Vineyard Systems. http://www.cdc.gov/niosh/test/n2-const/article-2340.html (accessed November 8, 2009), 2004. 34. Centers for Disease Control and Prevention. What is Health Marketing? http://www.cdc.gov/ healthmarketing/whatishm.htm (accessed October 9, 2009), 2005. 35. J. Tetroe. Knowledge translation at the Canadian Institutes of Health Research: A primer. Focus. Technical Brief No. 18. http://www.ncddr.org/kt/products/focus/focus18/. (accessed October 9, 2009), 2007.

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41

Overview of Ergonomic Research and Some Practical Applications in Sweden Lennart Dimberg CONTENTS 41.1 Introduction 41.2 Historical Background and Significance to Occupational Ergonomics 41.2.1 General Aspects 41.2.1.1 Labor Inspectorate 41.2.1.2 Work Environment Fund 41.2.1.3 Fund of Working Life 41.2.1.4 Occupational Health 41.2.2 Time Trends: Only Being Best Is Good Enough 41.2.2.1 Decentralized Organization and Increased Worker Involvement 41.2.2.2 Job Enlargement and Job Enrichment 41.2.2.3 Automation, Robots, and Computers 41.2.2.4 ISO 9000 and Total Quality Management 41.2.2.5 Process Organization Analysis 41.2.2.6 Kaizen 41.2.2.7 Worker Selection Process 41.2.2.8 Health Promotion and Worker Fitness 41.2.2.9 Flexible Working Hours 41.2.2.10 From Blue- and White-Collar Worker to Fellow Worker 41.2.3 Examples at Volvo 41.2.3.1 Kalmar Plant 41.2.3.2 Uddevalla Plant 41.2.3.3 Skövde Plant 41.2.3.4 Volvo Aero Plant 41.3 What Went Wrong? 41.3.1 Missing Link

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41.3.1.1 Theoretical Injury Mechanisms of Repetitive Strain Disorders 1100 41.3.1.2 Recent Research 1101 41.3.2 Rules and Regulations 1101 41.3.2.1 Workers’ Compensation System 1101 41.3.2.2 General Welfare System 1102 41.4 Critical Review of Current Status 1103 41.4.1 Nachemson Back Review 1103 41.4.2 Svanborg Study of 70-Year-Old People 1103 41.4.3 Methodological Problems in the Evaluation of Implemented Solutions 1103 41.5 Future Concerns 1104 41.5.1 Finding the Answers 1104 41.5.2 Implementing the Solutions 1105 Acknowledgments 1105 References 1105

41.1 INTRODUCTION The Scandinavian countries, especially Sweden, have a long history of concern for the health of their workers, Sweden being one of the first countries in the world to adopt regulations on the ergonomics of the work environment, The Swedish Ordinance Concerning Work Postures and Working Movements, in 1983 [1]. Sweden has 8.7 million inhabitants and one of the Western world’s highest proportion of female workers: 86% of women 15–64 years of age with children less than 10 years old had employment in 1988. It has 2.2 physicians per 1000 inhabitants, and in 1990, about 75% of all workers were covered by an occupational health program. The retirement age is 65 years of age, and in 1993, the unemployment rate was 8.8%. The Swedes have one of the world’s highest average life expectancies—78 years for women and 73 for men in 1992— and the second lowest infant mortality rate in the world (second to Japan). Volvo has used ergonomic designs for the interior of its cars for many years, and a study by Kelsey and Hardy [2] suggested that its low back support seats, developed in cooperation with orthopedic surgeons, reduced the frequency of lumbar disk surgery. Over the years, Volvo has transformed the worker-oriented approach into practical manufacturing examples in the car industry as well, in both the Kalmar (1974–1994) and Uddevalla (1985–1993) plants. However, in spite of all the work in the field of ergonomics, the number of reported work-related musculoskeletal injuries as well as overall sickness absenteeism continued to grow during the 1980s, and the Volvo workers were equally affected.

41.2 HISTORICAL BACKGROUND AND SIGNIFICANCE TO OCCUPATIONAL ERGONOMICS 41.2.1 General Aspects In Sweden, the first law on workers’ protection was adopted in 1912. In those days, the main problem was long working hours (12–14 h/day), which was thought to be the main reason for work-related accidents. In 1920, the 8 h workday was stipulated by law. A new

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law was adopted in 1949 that called for the introduction of mandatory health and safety committees in companies with more than 50 employees and worker safety representatives in companies with more than five employees. The National Board of Occupational Health and Safety was also formed. The current Work Environmental Act was adopted in 1977 and emphasizes the importance of prevention in both physical and psychological terms. It applies to all areas of occupational life, private and public sectors alike. Through special ordinances, this board instructs employers as to how the work environment law should be followed. From 1951 to 1992, agreements between management and the unions regulated the development of occupational health care services. Since 1993, these agreements have been under renegotiation. Occupational health care is not required by law. 41.2.1.1  Labor Inspectorate The National Board of Occupational Safety and Health is the central administrative authority in Sweden and is also the authority guiding the field organization, the Labor Inspectorate. The Labor Inspectorate is a law enforcement agency whose inspectors regularly monitor workplaces. In recent years, its actions have been directed more toward system inspection, looking at the structure of how health and safety work is organized and implemented. Traditionally, it has focused on accidents, and the implementation of ergonomic regulations has, relative to all the reported musculoskeletal work injuries, only rarely been enforced. 41.2.1.2  Work Environment Fund The work environment fund was founded in 1972 and grants research funding of about US $100 million per year (1990) for work environment-related research. 41.2.1.3  Fund of Working Life As of 1989, a special fee (1.5% of salary costs) has been paid to a work environment fund, which distributes grants totaling about US $300 million annually to employers for special projects on rehabilitation and improvement of the work environment. To receive funds, an employer must present a written program describing existing problems and showing plans to deal with them. The fund will pay part of the costs of projects that meet its criteria. 41.2.1.4  Occupational Health There are, in principle, three types of occupational health services in Sweden: in-plant service, out-of-plant group service, and branch service. In-plant service is the most common in the larger companies (with more than 1000 employees); out-of-plant service is most common in smaller companies; and branch service is representative of, for instance, the construction industry (Bygg-hälsan). In general, in the larger companies, there are 1 physician, 1 safety engineer, 1/2 physiotherapist, and 2 nurses per 2000 employees. Together, these professionals usually form a team to work with ergonomic problems.

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41.2.2 Time Trends: Only Being Best Is Good Enough Sweden has, like all other highly industrialized countries, a high cost of labor. Therefore, Swedish industry has found other ways of competing with low-cost countries, manufacturing high-value products with a focus on high technology, robotization, and a highly competent workforce. Swedish managers realize the high potential of a motivated worker, and a good work environment is an important motivator. However, now that high technology is readily available in low-cost countries as well and new computer programs make it easier to learn and use computers, the employers’ demand for the best possible team is understandable. This also constitutes a risk that sick or disabled workers will no longer be taken care of by employers. It is important to find a humane solution to this problem. 41.2.2.1  Decentralized Organization and Increased Worker Involvement Swedish companies like Sandvik, Asea Brown Boveri (ABB), Ericsson, and Volvo all have programs to decentralize their organizations. The hierarchy is flattened (fewer bosses), meaning that the number of decision levels is reduced to hasten the decision-making process. Work groups are being introduced, and supervisory responsibilities for planning, economy, quality, personnel, and production are shared among the workers. The goals of a group are set, and it is up to the group to decide on the means to achieve them. This has meant that health and safety matters are also delegated, which constitutes both an opportunity and a risk. If a worker needs an ergonomic chair or a lifting device, that can be decided on the floor, but there is also a risk that the specialized knowledge of rules and regulations is lost because the responsibility is now shared by several people. The Japanese have shown that worker participation in safety work is crucial to good results [3]. However, individuals with certain handicaps may need special consideration, which, in such groups, may not necessarily exist. Leif Wallin [4] developed an interesting method to have the group analyze their work situation by means of a questionnaire and subsequent discussion of the results. 41.2.2.2  Job Enlargement and Job Enrichment Since repetitive work, especially in fixed body positions, has been associated with muscular strain problems [5,6], occupational physicians have applauded when jobs have been enlarged. In the beginning, this often meant that a worker rotated between different, but similarly stressful, production operations—for example, from assembly to inspection of parts. It was clear that this was not enough to eliminate the repetitive strain problems. Also, work technique and its consequences for musculoskeletal disorders were evaluated by Kilbom and Persson [7]. Anyone who has played the guitar knows what the right technique means and the muscular fatigue of an incorrect technique. The recent ideas of enriching the work by introducing completely different types of work such as planning, economics, and quality may be a better way to prevent these problems, but this still remains to be shown.

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41.2.2.3  Automation, Robots, and Computers The fast growth of computer technology has meant that the next generation of industrial robots will be run by workers without extensive assistance from programmers and computer personnel. This clearly represents a breakthrough in the prevention of muscular pain problems. For example, a very high frequency of neck and arm problems was reported on a production line at Volvo Aero Corp., where connecting rods were made (Figure 41.1). An automatic process using a line of robots was introduced (Figure 41.2), and now the workers only have to watch and serve the machines, and orthopedic problems are rare. At the Matsushita Company in Tokyo that makes radios for Volvo, robots have now relieved women of tasks that gave them pains in the assembly of radios. 41.2.2.4  ISO 9000 and Total Quality Management Quality control is a fashionable term now in Sweden. The ISO 9000 quality standard calls for the documentation of every process and routine. Total quality management is an instrument of wider scope used to define, describe, and measure all processes and their relation to a business.

FIGURE 41.1  Manual work with connecting rods.

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FIGURE 41.2  A numerically controlled (NC) machine.

The quality of work in occupational health services also needs to be looked at. For example, in the field of ergonomics, there is often, out at the plants, a lack of prognosis and little or no follow-up of implemented ergonomic solutions to work-related health problems. 41.2.2.5  Process Organization Analysis Volvo’s main process is the manufacture of transport equipment. The role of occupational health services in this process concerns the prevention of injuries and diseases, the treatment of medical problems, and rehabilitation supporting the core process. In some companies, many of the peripheral processes such as cleaning and guarding are contracted outside the company. In-plant occupational health services have also been questioned by some companies, but experience of outside contracting is that quality deteriorates, and that is especially true of ergonomic work. 41.2.2.6  Kaizen It is clear that the closer one is to the workplace, the better one understands the problems. Many workers have suggestions not only on how to improve the quality of work but also on ergonomic solutions. The Japanese term kaizen means daily improvement, and this must also include the ergonomics of the workplace. It is important to act before the problems get out of hand. In Sweden, there has been a tendency to let the worker health and safety representatives (skyddsombud) deal with these problems through their organization. However, the law has recently been changed to emphasize that the employer alone is responsible, which has meant that these issues are now dealt with together with other production and quality issues. It is hoped that this will lead to the greater involvement of all workers in ergonomics.

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41.2.2.7  Worker Selection Process Over the years, much hope has been placed on preventing musculoskeletal problems by selecting the right workers for the job. Unfortunately, the conclusion reached by Kilbom and Hagberg [8] in a major literature survey is that no good screening program exists for the prevention of repetitive strain injuries. The idea that strength and fitness are of importance in the prevention of back problems [9] is contradicted by Battié’s prospective study at Boeing in Seattle [10], where only the number of previous back problems was a predictive variable. 41.2.2.8  Health Promotion and Worker Fitness Saab has developed a questionnaire and physical test that are presented to each participant to obtain a health profile. The general idea is that this profile should be an instrument for behavior change to a sounder lifestyle. Volvo has a similar program called the Life Line. In an evaluation, this has been shown to increase general well-being, but no preventive effect against muscular stain problems has been documented. A proven prophylactic program, however, has been the Volvo Back School, which is a prevention program that was used in a prospective, controlled study of patients with chronic back problems [11]. 41.2.2.9  Flexible Working Hours A system of flexible hours for blue-collar workers has also been implemented in some Volvo plants. It has the advantage of reducing stress associated with rigid shift hours, and workers with rheumatoid problems and morning stiffness may, for example, benefit from starting the workday somewhat later. 41.2.2.10  From Blue- and White-Collar Worker to Fellow Worker ABB and Volvo are presently discussing the problems associated with the separation of workers into blue- and white-collar collectives. From the perspective of rehabilitation, it has been shown to be very difficult, especially in a downsizing situation, to transfer, for example, a welder (blue collar) with a chronic neck problem to a suitable office (white collar) job. Here, the unions sometimes cannot agree.

41.2.3 Examples at Volvo 41.2.3.1  Kalmar Plant Attempts to facilitate the production by preassembly of, for example, doors were introduced at the original Torslanda factory, as shown in Figure 41.3. The vision of the Kalmar plant was to break the traditional line system. Involving the workers in more varied assembly work was expected to improve worker satisfaction, avoid repetitive strain injuries, and thereby increase quality. In the Kalmar plant, which was started in 1974, the mechanical conveyor belt was replaced by self-propelled trolley carriers (Figure 41.4) on which the car bodies were moved. The carriers were also equipped with tilting equipment so that work on the underside of the car could be performed in a comfortable posture. The work team became a factor in an endeavor to break down the impersonality of a big operation into sections that were easier to assimilate. The car was still moving between different workstations, but the trolley did not move during the time a given team was working on the car.

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FIGURE 41.3  Traditional car assembly line at Volvo Torslanda.

FIGURE 41.4  The moving line was broken at Kalmar and assembly performed on a stationary

platform.

However, even though the rate of reported muscular strain problems was lower at this plant compared to traditional line work, it was still unacceptably high. 41.2.3.2  Uddevalla Plant In 1985, the opening of the Uddevalla plant signaled a revolution in the process of making cars (Figure 41.5). The Uddevalla plant’s new methods were based on small work teams. Since each work team had a number of different tasks to perform and it was possible to lengthen the work cycles greatly, the individual team member’s work could be more varied.

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FIGURE 41.5  The concept of the Uddevalla plant.

The idea was that involving the team in planning, assembly, and quality work would provide so much variation that it would be mentally stimulating to the workers, and with this variation, one would also avoid all repetitive strain problems. In Uddevalla, the whole car was built at one station by a team of eight persons. Owing to a number of interesting ergonomic solutions, 80% of the time, the car could be manufactured in an upright ergonomically optimum body posture, as shown in Figure 41.6, by rotating it by 90°, compared to 20% in the old line system. Unfortunately, this did not prove to be the final solution for repetitive strain problems. In fact, the frequency soon increased to parallel the reported work accident frequency of the Kalmar plant. One reason was the high percentage of female

FIGURE 41.6  At the Uddevalla plant, 80% of the time the car was built in an upright economically

optimum body posture.

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assembly operators whose higher sickness absenteeism (40% higher than for male workers) was a contributing factor. Perhaps the main reason was that the cars were still being built almost completely by hand. Even if each particular assembly task was repeated only a few times per day, some assembly tasks required working with force in awkward positions. 41.2.3.3  Skövde Plant The moving platform system, originally implemented at the Kalmar plant, has come into widespread use. In the new engine line at Skövde, the platforms have individually adjustable fixtures (Figure 41.7), which clearly afford less musculoskeletal strain. In this plant, an almost totally automated production line for gearboxes has shown the way to completely avoid manual assembly and thereby repetitive strain problems. 41.2.3.4  Volvo Aero Plant Manual deburring of turbine blades for jet engines (Figure 41.8) has, over the years, caused large numbers of muscular strain problems in the neck and shoulders. The final solution to this problem turned out to be the introduction of a deburring robot (Figure 41.9).

FIGURE 41.7  The engines at the Skövde plant are built on platforms with individually adjustable

fixtures.

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FIGURE 41.8  Manual polishing of turbine blades.

FIGURE 41.9  A deburring robot.

41.3 WHAT WENT WRONG? 41.3.1 Missing Link Given the fact that improved ergonomics in general has not resolved the problem of repetitive strain injuries, one may speculate as to whether or not the injury mechanism really is clearly understood. Is there a missing link?

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41.3.1.1  Theoretical Injury Mechanisms of Repetitive Strain Disorders In a review article, Hagberg [12] summarizes injury mechanism. The following paragraphs draw strongly on that article. Degenerative joint disease—osteoarthrosis or osteoarthritis—may be caused by increased stress on the cartilage, such as repetitive impulsive loading. According to some authors, this is sometimes preceded by trabecular microfractures in the subchondral bone caused by trauma. Other authors point to clinical evidence of polyarticular disease and suggest a metabolic abnormality of the articular cartilage. It is claimed that insertion disorders in tendons, ligaments, and articular capsules are caused by local ischemia leading to degeneration and producing inflammation and pain. In particular, the tendons of the supraspinatus, the biceps brachii, and the upper part of the infraspinatus muscles have a zone of avascularity. This has been found to be the site of microruptures and degeneration that may be accelerated by aging. Impairment of the venous circulation may occur when the humeral head compresses the tendons (elevated arm) but also when there is increased tension in the tendon. Tendon inflammation has been provoked by repetitive contractions in rabbits. Degenerative tendinitis in the shoulder girdle aroused by exertion, for example, may trigger a foreign body response inflammation. Tenosynovitis is an inflammation of the tendon sheath and its synovia. In the long biceps tendon, this may be caused by the tendon and its sheath rubbing against the lesser tuberosity during overhead movements. Postinfective arthritis as well as tendinitis may presumably predispose a person exposed to shoulder stress to a more severe reaction. Muscle tenderness, myofascial syndrome, trapezius myalgia, and related disorders are obscure conditions because the pain does not originate from the contractile muscle fibers themselves. It may possibly derive from pain fibers within the blood vessels or the connective tissue. Hagberg [12] points to three pathophysiological routes. The first is mechanical failure with ruptures of Z-disks probably caused by temporary high local stress. The second is local ischemia due to the impairment of the circulation by continuous muscular performance, which may already occur at 10%–20% of the maximum voluntary contraction. This leads to a fall in pH and reversible enzyme inhibition. It is postulated that the tissue irritation causes extravasation of blood, edema, and fibrositis in some individuals. Highly repetitive work may then possibly cause cumulative trauma to the muscle cell [thence cumulative trauma disorders (CTDs)], affecting both morphology and energy metabolism. The third pathophysiological route would be energy metabolism disturbance. Energy depletion in the muscle cell has been suggested as one factor in muscle pain. Defects in the energy metabolism are often associated with painful disorders of the muscle. Laboratory experiments involving repetitive shoulder flexions have produced energy depletion as indicated by an increasing serum creatine kinase and accompanying pain. It is hypothesized that this may also be important for static loads. The possibility of certain primary metabolic disturbances in certain individuals has also been proposed.

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The carpal tunnel syndrome is a textbook example where the injury mechanism is clearly understood. Friction-caused synovitis of the tendon sheaths in the carpal tunnel causes pressure on the median nerve [13]. Another example is supraspinous tendinitis, where the supraspinous tendon is pressed against the acromion in a space that has been limited by inflammation [14]. Fibrositis/fibromyalgia and generalized muscular pain is a common condition but with a poorly understood pathogenetic mechanism. The theory that static muscular work causes ischemia in the muscle, creating morphological changes in the muscle fibers, has been suggested but remains to be proved [15]. It is easy to prove muscular fatigue and pain after minor static load [16,17], but the pathogenic link from repetitive chronic muscular fatigue to permanent damage and chronic pain remains to be shown. Microfractures have been suggested by Hansson et al. [18] to be the reason for back pain in certain individuals, but no one knows how common this is. The lumbar disk and its degeneration have been connected to low back pain, and the intradiscal pressure as measured by Nachemson and Elfström [19] was for a long time the theoretical mechanism for ergonomic advice on lifting but has since been abandoned by Nachemson [20]. Spinal shrinkage as measured from height before and after loading provides a method for measuring mechanical load on the spine [21]. The shrinking is dependent on the elasticity of the intervertebral disks. However, no one knows if the shrinkage leads to permanent disk problems or whether this may be a pathogenetic mechanism for back pain. 41.3.1.2  Recent Research Overview: Recent Swedish research on ergonomics has broadened the concept from physical workplace adjustment to psychological factors [22] and sociological aspects of work groups and leadership [23]. A comprehensive literature survey and analysis of health risks at work has been performed by the National Swedish Commission for the Work Environment [8]. Its conclusion is that the prevalence of and risk factors for many disorders in the locomotor system are still not satisfactorily known.

Case studies: Evaluations of the use of an ergonomic chair, the Ullman chair, as a secondary prophylaxis for low back problems has shown significantly less pain and fewer sick days for low back pain in this group than in a randomized control group using a traditional office chair in a 1-year prospective study [24]. Also, prophylactic inversion therapy (autotraction) by the Swedish Mastercare Inversion System (Svenska Hälsobänken) with self-training for 10 min daily has been shown to reduce the pain score significantly in chronic low back pain patients in a 1-year study at Volvo Aero Corp. [25]. 41.3.2 Rules and Regulations 41.3.2.1  Workers’ Compensation System The Swedish workers’ compensation system introduced in 1977 has been one of the most liberal in the world. This may be one explanation why Swedish industry, in spite of sub-

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stantial improvements in the physical work environment and ergonomic advances, has had about the highest rate of work injuries in the world. The acceptance of a work injury is based on two steps, the first being that a disorder should be known to be caused by work. If that was the case, in the next step, even a very low probability would allow a claim to be recognized as a work injury. This caused an explosion of filed claims for most pain problems involving the locomotor system, and over 90% were accepted as work injuries. The acceptance of a work injury meant full salary during sick leave, and, in addition to this, compensation of pain and suffering and medical disability would provide the claimant with considerably more money than the regular salary and there was no incentive to return to work. There are several persons in Sweden with claimed muscular pain in the neck and shoulders that, at less than 30 years of age, have gone into early retirement in spite of few objective findings! In July 1993, the law was changed so that it now takes a high probability for work to be considered the causal factor of medical complaints. 41.3.2.2  General Welfare System Sweden has for many years had a very liberal and generous health insurance paid by the government through equal fees from all employers. Although the Swedes have one of the highest life expectancy rates in the Western world, we also have one of the highest rates of sickness absenteeism. Although the Volvo plants had an average sickness rate of 12% among their blue-collar workers in 1991, it is important to know that two-thirds of these workers take sick leave less than 1 week/year. In 1991, the law was changed so that employers pay directly for only the first 2 weeks of sick leave, and the first 3 days of sickness compensation was reduced from 90% to 75% of the worker’s salary. In 1992, the sickness rate decreased by 1.3% for blue-collar workers. When, in April 1993, a 1-day waiting period 800

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FIGURE 41.10  Sick reports by Volvo Flygmotor (3000 employees) during the time of a change in

the compensation system. One day without pay was introduced in April 1993.

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(with no pay) was introduced for health insurance, the number of sick reports per day at Volvo Aero Corp. was reduced by about 50% (see Figure 41.10). Against this background, it is probable that the real benefit of ergonomic applications in the work environment has been shadowed by effects of the health insurance system.

41.4 CRITICAL REVIEW OF CURRENT STATUS 41.4.1 Nachemson Back Review In a major survey of international studies on low back pain, Nachemson [20] claims that very few prospective and controlled studies on work relatedness exist. He concludes that even if the effect of physical factors cannot be denied, work satisfaction seems to be the most important predictor of future work-limiting back problems. The importance of early and active rehabilitation is emphasized. 41.4.2 Svanborg Study of 70-Year-Old People In one of the largest cross-sectional studies published to date, Svanborg [26] interviewed in great detail and physically examined some 700 70-year-old men and women in Göteborg. He concludes that there was no difference in the prevalence of pain problems in the locomotor system between the workers who had performed heavy manual labor and those who had been office workers. The only difference noted was that the former were physically stronger and had higher bone density. The group has since been followed for 10 years. At age 79, previously sedentary workers were more disabled in activities of daily living than those whose work had been physically strenuous. 41.4.3 Methodological Problems in the Evaluation of Implemented Solutions Hagberg et al. [27] pointed out some methodological aspects that call for brief comment. The evaluation of doses of exposure to repetition injuries and the dose–response correlation is important. The diagnostic criteria should be stringent. Unfortunately, only a few clinical tests have been validated, and these clinical tests may be helpful for confirming a diagnosis but not for excluding a disease [28]. Ideally, an age-, gender-, and education-matched control group should be used to evaluate suggested ergonomic changes because over a period of time, job content may change, new work processes may be implemented, some workers may be transferred to other departments, and so on, which may be the real reason for improvements in health rather than the ergonomic solution. Also, time could be a healing factor that coincides with ergonomic change. Other factors such as tobacco use and alcohol consumption should also be checked [29]. The use of visits to physicians as an endpoint for measuring the prevalence of certain conditions such as tennis elbow at the workplace is not a good method. Workers with tennis elbow are more prone to see a doctor for their problem if they have a heavy job even if the real prevalence of tennis elbow is the same among workers in heavy and light jobs [30]. Swärd [31] studied top athletes and found that 85% of male gymnasts experience some low back pain and 54% have severe low back pain. Still they can operate at the top international level. Sickness absenteeism as a measure of the problem is thus seen to be affected by many psychological and motivational factors.

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41.5 FUTURE CONCERNS 41.5.1 Finding the Answers The criticism from Nachemson, the Svanborg study, and my own experience indicated that the irreversible chronic low back pain syndromes, neck/shoulder pain, fibrositis, etc., in many cases have a causative background (metabolic, infectious?) other than work. Work may aggravate aches and pains, but the aches and pains probably had another origin. It is important to distinguish between the pathological process and the provoking factor that produces pain. In such cases, ergonomic solutions may be of some help to the individuals but will usually not solve the problem. The typical muscle strain work injury should be improved if working conditions are improved by, for instance, ergonomic changes. To be a candidate for ergonomic intervention, an injury should comply with most of the nine criteria stated for causation by Sir Bradford Hill [32]: 1. Strength of association: High odds ratios mean a strong association. 2. Consistency: Repeatedly observed by different investigators in different countries. 3. Specificity of the association: The injury is limited to the exposed persons. 4. Temporal relationship: Effects appear after the cause. 5. A dose–response curve: The higher the dose, the greater the number of cases. 6. Biological plausibility: The biological mechanism should be understood.

7. Coherence of evidence: Cause and effect should not seriously conflict with the generally known facts of natural history and biology.

8. Reversible association: As an example, when smokers stop smoking cigarettes, the rate at which they develop lung cancer should fall. 9. Analogy: After having discovered a drug effect of thalidomide on fetuses, we are more ready to accept fetal effects by other drugs. The missing link of a pathologic process may suddenly appear. The etiologic process is better understood when, as in the case of rheumatoid arthritis, the immunologic mechanism is discovered. New imaging techniques such as magnetic resonance imaging (MRI) make it possible to visualize soft tissue and verify, for instance, changes in the carpal tunnel that explain the pain. The ultimate prerequisite for an ergonomic solution is that the pathogenetic mechanism is understood in detail. The Swedish National Commission for the Work Environment (Arbetsmiljökommissionen, 1989 [8]) suggests that a systematic follow-up of implemented ergonomic solutions should be performed. Many suggested modifications are based more on individual ideas than on a solid base of knowledge.

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41.5.2 Implementing the Solutions Compiling and using collected examples of evaluated ergonomic modifications such as those published by Oxenburgh [33] is one way of implementing ergonomic solutions. A  possible vision is that the next generation of intelligent, seeing, and feeling industrial robots will take over all the highly repetitive tasks that continue to provoke discomfort and pain in human workers.

ACKNOWLEDGMENTS I particularly wish to thank Ulf Jeverstam, AM Volvo, for valuable advice on the manuscript; Mats Ericson, Royal Swedish School of Technology, for critical comments; Dennis Savage for reviewing the language; and Sture Hård, Gothenburg University Medical Library, for help with the references.

REFERENCES 1. Arbetarskyddsstyrelsens författningssamling (Swedish), The Swedish Ordinance Concerning Work Postures and Working Movements, 1983:6. 2. J. L. Kelsey and R. J. Hardy, Driving of motor vehicles as a risk factor for acute herniated lumbar intervertebral disc, Am. J. Epidemiol. 102(1):63–73 (1975). 3. K. Noro, Participatory Ergonomics: Concept, Advantages and Japanese Cases in Human Factors in Organizational Design and Management, North-Holland, Amsterdam, the Netherlands, pp. 83–86 (1990). 4. L. Wallin, Modification of work organization, Ergonomics 30(2):343–349 (1987). 5. S. Kvarnström, Occurrence of musculoskeletal disorders in a manufacturing industry with special attention to occupational shoulder disorders, Scand. J. Rehabil. Med. Suppl. 8:1–144 (1983). 6. L. Dimberg, A. Olafsson, E. Stefansson et al., The correlation between the work environment and the occurrence of cervicobrachial symptoms, J. Occup. Med. 31(5):447–453 (1989). 7. Å. Kilbom and J. Persson, Work technique and its consequences for musculoskeletal disorders, Ergonomics 30(2):273–279 (1987). 8. Å. Kilbom and M. Hagberg, Arbeten utsatta för särskilda hälsorisker, Arbetsmiljökommissionen, Swedish, 1989. 9. S. H. Snook, Approaches to preplacement testing and selection of workers, Ergonomics 30(2):241–247 (1987). 10. M. C. Battié, The reliability of physical factors as predictors of the occurrence of back pain reports. A prospective study within industry, Thesis, University of Göteborg, Gothenburg, Sweden, 1989. 11. A. Nachemson, I. Lindström, C. Öhlund et al., Symposium om “ryggproblemens lösning,” Läkartidningen 85(50):4437 (1988) (in Swedish). 12. M. Hagberg, Occupational musculoskeletal stress and disorders of the neck and shoulder: A  review of possible pathophysiology, Int. Arch. Occup. Environ. Health 53(3):269–278 (1984). 13. G. Lunborg, Nerve Injury and Repair, Churchill Livingstone, New York, 1988. 14. P. Herberts, R. Kadefors, C. Hogfors et al., Shoulder pain and heavy manual labor, Clin. Orthop. 191:166–178 (1984). 15. K. G. Henriksson, Exercise induced myopathies in man, Opuscula Med. 28(2):34–37 (1983). 16. M. Hagberg, On evaluation of local muscular load and fatigue by electromyography, Arb. Hälsa 24:1–53 (1981).

1106    ◾    Occupational Ergonomics: Theory and Applications 17. B. G. Jonsson, J. Persson, and Å. Kilbom, Disorders of the cervicobrachial region among female workers in the electronics industry. A two-year follow up, Int. J. Ind. Ergon. 3:1–12 (1988). 18. T. Hansson, T. Keller, and R. Jonsson, Fatigue fracture morphology in human lumbar motion segments, J. Spinal Disord. 1(1):33–38 (1988). 19. A. Nachemson and G. Elfström, Intravital dynamic pressure measurements in lumbar discs. A  study of common movements, maneuvers and exercises, Scand. J. Rehabil. Med. (Suppl.) 1:1–40 (1970). 20. A. Nachemson, Ont i ryggen, orsaker, diagnostik och behandling, SBU, 1991, (in Swedish). 21. M. Ericson and I. Goldie, Spinal shrinkage with three different types of chair whilst performing video display unit work, Int. J. Ind. Ergon. 3:177–183 (1989). 22. T. Sivik, Diagnosis and treatment of patients with idiopathic low back pain, Thesis, University of Göteborg, Gothenburg, Sweden, 1992. 23. L. Dimberg, L. Wallin, and B. Eriksson, Unpleasant atmosphere at work increases the risk of musculoskeletal disorders, Läkartidningen 88(11):981–985 (1991) (in Swedish). 24. L. Dimberg, M. Ericson, and J. Ullman, The effects of low back pain and disorders by sitting in non-traditional chairs with forward sloping seats compared to traditional chairs with horizontal seats, Proc. Swedish Med. Assoc. (Riksstämman) 46:121 (1992) (in Swedish). 25. L. Dimberg, L. G. Josefsson, and B. Eriksson, Prophylactic inversion therapy in chronic lowback pain patients in the workplace—A prospective, randomized controlled study, Proc. Swedish Med. Assoc. (Riksstämman) 9P:114 (1993). 26. A. Svanborg, 70-Year-old people in Gothenburg, Sweden: A population study in an industralized Swedish city. Practical and functional consequences of aging, Gerontology 34(Suppl. 1): 11–15 (1988). 27. M. Hagberg, L. Jorulf, and Å. Kilbom, Methodologic Problems in Muscular Strain Epidemiology, Natl. Inst. of Occupational Health, Sweden, Report 19, 1988 (in Swedish). 28. E. Viikari-Juntura, Interexaminer reliability of observations in physical examinations of the neck, Phys. Ther. 67:1526–1532 (1987). 29. L. Dimberg, A. Olafsson, E. Stefansson et al., Sickness absenteeism in an engineering industry— An analysis with special reference to absence for neck and upper extremity symptoms, Scand. J. Soc. Med. 17(1):77–84 (1989). 30. L. Dimberg, The prevalence and causation of tennis elbow (lateral humeral epicondylitis) in a population of workers in an engineering industry, Ergonomics 30(3):573–579 (1987). 31. L. Swärd, The back of the young top athlete. Symptoms, muscle strength, mobility, anthropometric and radiologic findings, Thesis, University of Gothenburg, Gothenburg, Sweden, 1990. 32. B. Hill, Association is not causation, in Principles and Practice of Research for Surgical Intervention, H. Troidl, W. O. Spitzer, B. McPeek et al., Eds., Springer-Verlag, New York, 1986. 33. M. S. Oxenburgh, Increasing production and profit by health and safety, Sydney and Chicago’ CCH International, 1991.

Chapter

42

Current Status of the Ergonomics Research in China He Lihua, Sheng Wang, and Bingshi Wang CONTENTS 42.1 Preamble 42.2 Development of Ergonomics in China 42.2.1 Development of Research Disciplines and Organizational Societies 42.2.2 Academic Progress References

1107 1108 1108 1109 1116

42.1  PREAMBLE Although the formation and development of ergonomics has had a history of more than a century, it was only in the last 20 years that ergonomics assumed greater importance in China, which has accelerated growth in every related field. The United Kingdom is one of the pioneering countries that initiated ergonomics research. A British scholar formed the word “ergonomics” with the Greek words “ergo” (work or effort) and “nomics” (law or normalization), that is, “ergonomics” means “work normalization” or “natural law of work.” In the development of ergonomics, due to different research foci, scientists from different countries and regions have provided varied designations to this science. For example, in the United States, it is called “human factors” or “human engineering”; in Japan, it is called “人間工学（にんげんこうがく).” The universal designation for this science is now “ergonomics,” and China adopts this designation. Ergonomics, as a comprehensive application discipline, has a broad scope for research. It involves every aspect of human work and general living environment. The research in relation to work is called “occupational ergonomics.” Occupational ergonomics is the study of relationships among humans, machinery, equipment, and their environment in order for people to stay healthy and work in a safe, comfortable, and effective manner.

1107

1108    ◾    Occupational Ergonomics: Theory and Applications

42.2  DEVELOPMENT OF ERGONOMICS IN CHINA 42.2.1  Development of Research Disciplines and Organizational Societies The study of ergonomics in China started very late. Although some research work in ergonomics started in the 1930s, it did not become an independent research field until the 1980s. In 1980, universities and research institutes in China started to set up ergonomics labs. In the 1980s, the first Chinese treatise on ergonomics was published and the occupational hygiene textbooks in colleges began to have chapters on occupational ergonomics. In 1980, the China Technical Committee of Ergonomics Standardization Administration was founded in Beijing. It is responsible for centralized planning, conducting research, and reviewing the establishment of the national ergonomics standards. In 1984, the State Commission of Science and Technology for National Defense Industry established the National Military Human-Machine-Environment System Engineering Standardization Technical Committee. The establishment of these two commissions was a big catalyst to the development of ergonomics research in China. In 1989, the Chinese Ergonomics Society (CES) was founded. In November 1989, the Safety and Environment Ergonomics Subcommittee of CES was founded which was later followed by the establishment of Ergonomics Management Subcommittee of CES and Human-Machine Engineering. Currently, CES has seven branches: cognition commission, human-machine engineering commission, biomechanics commission, safety and environment commission, ergonomics standardization commission, ergonomics management commission, and transportation ergonomics commission. Professor Walter Rohmert, a famous international ergonomics scholar and the former director of the Labor Science Research Institute of Technische Universität Darmstadt, had a great interest in the promotion of ergonomics in China and was very friendly to the Chinese ergonomics researchers. He always said that if ergonomics were not promoted in a large country like China, it would have been a very big deficiency for the world. With his drive and influence, at the meeting of the board of directors of the International Ergonomics Association (IEA) held in Paris in July 1991, with majority votes from the directors, CES was accepted as the member of the IEA. This was a milestone in the development of Chinese ergonomics. CES irregularly publishes newsletters, providing the latest news about CES, other affiliate societies, international academic trends, ergonomics research publication information, etc. [1–7] are some publications during that period. In September 1995, CES formally published the academic magazine Ergonomics. In the early 1990s, the Beijing University of Aeronautics and Astronautics established the first program for a doctoral degree in ergonomics. Since then, the Psychology Research Institute of the Chinese Academy of Sciences (CAS), Nanjing University of Aeronautics and Astronautics, Beijing Institute of Technology, Peking University, Tsinghua University, Zhejiang University, and approximately 100 other universities and research institutes have successively established ergonomics majors and research areas. In 2005, CES established its website for the convenience of research and information exchange and for the promotion of the development of ergonomics. In August 2009, CES successfully hosted the 17th International Symposium on Ergonomics in Beijing.

Current Status of the Ergonomics Research in China    ◾    1109  

42.2.2  Academic Progress The study of ergonomics in China started late. In the 1930s, the beginning stage of the Chinese ergonomics, in order to meet the application needs in the industry, Chinese psychologists introduced the concept of industrial psychology from western countries into China. Since then, ergonomics has been a research field in China. Some scholars conducted research projects on engineering psychology related to work fatigue, working environment, worker selection test, etc. In the 1950s, psychologists from the Institute of Psychology, CAS, and Hangzhou University conducted research on work psychology in the areas of operation optimization, technological innovation, accident analysis, employee training, etc. These research studies played an active role in increasing work efficiency and productivity. In addition, some scholars conducted research on the standardization of the design of gas masks, gloves, clothes, and airplane cabins. In the 1960s, some scholars shifted the focus of their research to human–machine interface relationships, such as engineering psychology covering areas such as railway signal display, power station control signal display, instrument display panel design, aviation illumination, aircraft cabin instrument display, etc. These research efforts established a firm foundation for the development of the ergonomics in China. In the late 1970s, the research on industrial psychology developed very rapidly in China. These research efforts on engineering psychology mainly focused on fundamental applications of ergonomic principles. At present, there are many research projects dealing with driving safety and human–machine interaction [13,18–20,23,30]. The researches on driving behavior have found that the verbal communication behavior and the automobile-­driving behavior have mutual impact on each other. The driver who is actively involved in conversation with another person is likely to be more affected. Furthermore, research studies also showed that when evaluating braking reaction, speech speed and speech repetition frequency are effective indices for evaluating the effect of conversation on driving behavior. Based on these findings, researchers at present mainly focus on measuring a driver’s mental load, situational awareness, and fatigue in relation to electrophysiology. These types of research studies have generated some beneficial outcomes. In recent years, other research studies in addition to driving safety research work have included spatial cognition, stimulation–­reaction compatibility, etc. Those research results provide design principles for manual control interface design that conforms to the human psychological processing. As a result of rapid growth in computer science and technology, scientists from China have made significant contributions to the technology for Chinese character recognition and input into computer. These research efforts provided psychological evaluation principle of compatibility for a variety of Chinese character input methods. Based on the principles of cognition psychology, these research studies brought forward the design principles for stroke and chord keyboard Chinese character input methods. While the development of Chinese character handwriting recognition technology was just beginning, scientists discovered through mathematical modeling and experimentation the functional relationships among handwriting recognition time and recognition rate and word database size.

1110    ◾    Occupational Ergonomics: Theory and Applications

Based on this research, they defined the optimal handwriting recognition time setting. Thus, they solved the problem of the user’s subjective perception of being delayed caused by the conflict between the recognition waiting time and word base size. In the late 1990s, many multinational corporations, led by Motorola, took interest in the Chinese market and set up R&D centers and product manufacturing bases in China. In order to meet the demands of Chinese consumers, they cooperated with Chinese researchers and carried out many research projects for product localization, such as the definition of the cognition styles of the Chinese users, analysis of the usability of the Chinese translation of their products’ English menus, etc. At the beginning of the twenty-first century, usability measurement made significant progress in China. In the past 2 years, the usability research has not only focused on the evaluation of the usability of prototype products but also emphasized on the discovery of user psychological models as well as the cognition of the processing mechanism during the product use process. For example, research on the multimode word input interface has discovered the bottleneck of the cognition of the voice recognition technology in mobile communication application. This finding has defined the direction for the future development of the voice recognition technology. At present, research on engineering psychology in China has expanded to all sectors and industries including manufacturing, agriculture, transportation, health care, aerospace medicine, etc. It has also promoted the integration of this science with other engineering technologies and related sciences. Therefore, without a doubt, engineering psychology has become a very important interdisciplinary subject in China. Ergonomics standardization means defining the requirements, standards, or codes for the products, facilities, and environmental conditions designed for human according to the principles of ergonomics. The establishment of ergonomics standards has played a very important role in improving people’s work condition and quality of life and promoting the development of production and technology for the society. The China Technical Committee of Ergonomics Standardization Administration (TC7) mainly focuses on the standardization of the terminology, methodology, and human factor data in ergonomics. See Table 42.1 for corresponding of TC159 to ISO. Since 1980, through systematic planning, research, and review by the China Technical Committee of the Ergonomics Standardization Administration, China has established a TABLE 42.1  Comparison between ISO and China Technical Committee of Ergonomics Standardization Administration

Name No. Setup of branch technical committees

International Standardization Organization TC159 SC1 (ergonomic guiding principles) SC3 (anthropometry and biomechanics) SC4 (ergonomics of human–system interaction) SC5 (ergonomics of the physical environment)

China Technical Committee of Ergonomics Standardization Administration TC7 SC1 (ergonomics guiding principles) SC3 (anthropometry and biomechanics) SC4 (signal, display, and control) SC5 (physical environment) SC8 (lighting) SC9 (labor safety)

Current Status of the Ergonomics Research in China    ◾    1111  

set of relatively comprehensive ergonomic standard systems. By the end of 2007, this committee had issued 45 national ergonomics standards. In general, the Chinese ergonomics standards are divided into four levels: national standards, national military standards, industrial standards, and corporate standards. These standards form an organic entity, but each one as well focuses on different fields [17,28,35,42]. The current ergonomics standard system consists of three parts: ergonomic guiding principles, anthropometry and biomechanics, and ergonomics of human–system interaction and ergonomics of the physical environment. These standards almost encompass every aspect of ergonomics including ergonomics of lighting and ergonomics of labor safety. Recently, China established the human–machine system interaction national ergonomics standard system. It includes human–machine interaction system universal design standards, design standards for visual display terminal, multimedia user interface, mental load, and operating with flat visual display panel. These standards are mainly used for research and development, design of the products in the related fields, and technical support role. Biomechanics is an interdisciplinary subject that explores the use of laws of mechanics to better understand the movement of biological systems. Its primary focus is to explain various phenomena of biological bodies with established principles and viewpoints of the physics of motion. It studies the mechanical aspects of biological systems, such as humans, animals, organs, and cells, and elucidates their mechanical properties and their relation with the functions of biological systems using traditional theories of mechanics, in order to solve the problems existing in biomedicine, sports, and work. The scope for research in biomechanics is very broad, and its research contents are very rich. Occupational biomechanics is the science of studying the stress imposed on individuals as a result of physical tasks at workplace. The field of occupational biomechanics focuses on reducing workplace injuries, protecting the health of workers, and increasing their job competence. The main research contents of occupational biomechanics are the musculoskeletal system, movement characteristics, mechanical/structural characteristics, and biomechanical models in different occupation and work environment; mechanical issues under different postures; special measurement and analysis methods; optimization of machine and tool design to accommodate the worker anthropometry and their work capacity; and related standards and specifications. In the mid-twentieth century, biomechanics research efforts in China were mainly focused on sports medicine and athletics. At the beginning of the 1970s, China started research on occupational biomechanics. In the 1980s, biomechanics research mainly focused on investigating the effect of work postures (such as standing, sitting, and carrying heavy loads) on musculoskeletal stress and their relation to musculoskeletal diseases [3–12,29,31,34]. Chinese scholars, based on the development of anthropometry, established mechanical models for the stressed body parts of sitting operation including neck, shoulder, wrist, waist, etc. [14–16,21–25,36,37]. Those models allowed the calculation of the stresses associated with everyday working postures. Sheng Wang et al. [8–10] established waist and neck biomechanical models based on the biomechanical analysis of the workers involved in the production process in the electronics industry. In the 1990s, computer-based automatic

1112    ◾    Occupational Ergonomics: Theory and Applications

analysis system, mechanical analysis, and synchronous analysis of bioelectrical and physiological functions were used by researchers in China [20,21,25]. The proper operation postures for sitting work were also studied. As the research went further, methodology was improved greatly. Experimental study was carried out for both standing and sitting operations. In the twenty-first century, as modern sciences and technologies are developed and applied, more advanced methods and approaches are becoming available for occupational biomechanics research and promote its future development. For example, the three-dimensional (3D) motion data collection and processing system has significantly replaced the manual motion analysis method. This system can quickly and accurately collect and analyze the biomechanical parameters of human body movement in the 3D space. Additionally, the combination of 3D dynamic biomechanical modeling and field surveys can provide the quantitative relationship between occupational risk factors and disease occurrence rate. In recent years, research on occupational biomechanics has started to deepen into micro-level analysis to study muscle, tendon, ligament, and skeleton tissues at cellular and molecular level [24,27,40]. Occupational biomechanics has made great progress in the research on the pathogenesis and preventive measures of chronic musculoskeletal disorder, a frequently encountered occupational disease. In the medical field, ergonomics is closely related to occupational hygiene. In terms of protecting the health and safety of the workers, ergonomics and occupational hygiene have different research approaches but the same research objectives. Much research about the human body and environment in ergonomics utilizes the knowledge and methodology of occupational hygiene. On the other hand, research results in ergonomics can be used in industrial hygiene to improve workers’ health. In China, in occupational textbooks, ergonomics is defined as the science that is human oriented, researching the relationships among people, machinery, and the environment with the objective of ensuring the health, safety, and comfort of workers while promoting work efficiency. As early as the 1960s, Chinese researchers started to pay attention to musculoskeletal disease. For example, manual material handling workers frequently had flatfoot and low limb varix disorder. However, elective classes in ergonomics and biomechanics in academic institutions had not been offered until ergonomics became an independent research disciplines in China. In the 1980s, some scholars began to study the relationship between workload and musculoskeletal diseases. Their research focus was mainly on labor-intensive workers, such as stevedores, refinery workers, construction workers, etc. Meanwhile, biological models were developed based on the characteristics of body mechanics, and workload standards were established regarding how to apply force reasonably. The School of Public Health, Peking University, carried out epidemiological surveys of the worker population and studied the relationships among different work tasks, different body parts, and work-related diseases and musculoskeletal disorders [8–10]. They also conducted ergonomic assessments. Tables 42.2 and 42.3 show work-related musculoskeletal disorders (WRMDs) and their prevalence in different types of work. As the use of computer became prevalent, production processes started to change and resulted in changes of workload at the workplaces. With increased use of computers, the occupational health problems research focus shifted to the use of VDT (video display

Current Status of the Ergonomics Research in China    ◾    1113   TABLE 42.2  Comparison of 12 Month Prevalence and Point Prevalence in Different Body Parts Point Prevalence Body Parts Neck Shoulder Wrist

12 Month Prevalence

n

%

n

%

125 228 48

7.6 13.9 2.9

278 585 171

16.9 35.8 10.5

TABLE 42.3  Prevalence of WRMDs in Different Body Parts Categorized by Type of Work Prevalence (Five) Work Type

Number

Neck

Shoulder

Wrist

Preparing Molding Plastering Operating Packaging Testing

81 114 251 183 788 219

20.9 17.5 20.7 10.3 18.4 12.3

46.9 37.7 50.6 37.7 31 28.8

7.4 13.2 9.2 8.2 11.3 7.8

terminal, or sometimes referred to as visual display terminal). Those topics are visual strain analysis, fatigue factors analysis, musculoskeletal disease such as carpal tunnel syndrome, impact of radiation on the female reproduction system, and visual display and control panel ergonomics design. In the 1990s, as science and technology developed further, assembly-line-style work became dominant in industries. During this time period, research studies were carried out in the area of assembly-line WRMDs as well as the effect of shift work on labor competence. Studies were also carried out dealing with WRMD associated with repetitive and monotonous work such as sewing, typesetting, etc. In the twenty-first century, as the pace of people’s life became faster, social psychological factors became prominent risk factors. As a result, many industries started to pay attention to the psychological factor of employees. For example, research studies on medical staff’s mental workload and emergency response, placing more emphasis on improving the task arrangement, proper job assignment, and efficiency, became of great importance. In spite of all the efforts made so far, WRMD is still one of the major concerns of the current occupational ergonomics. Using foreign WRMD standards questionnaires as a reference, Chinese researchers have established WRMD questionnaire which is more suitable for China [38,41]. Work environment research topics include analysis of the effect of physical work performed with exposure to environmental factors such as heat, cold, or high altitude and its impact on the body and work efficiency. Such research efforts help define optimal working condition. For example, by studying the temperature at workplace, scientists can define the optimal temperature needed for the workplace; by studying the noise level, they can define the optimal sound levels that do not affect normal verbal communication nor cause distraction. They are

1114    ◾    Occupational Ergonomics: Theory and Applications

also able to define the optimal illumination needed for performing visually demanding tasks. Also, research studies were carried out on ergonomic assessments of workplace and workstation design. Based on those research studies, corresponding standards have been established. By 2007, 25 standards related to occupational health had been established in China. Among these national standards, some are mandatory and others are used as guidelines. Among all the occupational ergonomics standards, the research on workplace safety is the most successful (such as the machine safety guard distance and personal protection clothing requirement national ergonomics standards). Other ergonomics standards also have generated noticeable social and economic benefits. In China, ergonomics research emphasizes on applications more than theory. Many scholars devote themselves to the application of general theories and methods of ergonomics in the actual design cases. They have achieved excellent results in product modeling, workplace design, and interface design and have gained a lot of experiences. Some researchers have performed literature reviews of over 4000 scientific journals in search of ergonomic research works done by Chinese scholars from 1994 to 2003 [13]. Literature search analysis showed that there is an increasing trend in research dealing with applied ergonomics in China. Based on the data shown in Figure 42.1 [2,13], applied ergonomics has received progressively more attention from all industries, sectors, and academic fields. Researchers also summarized and analyzed the treatises published during the period of rapid development in ergonomics in China (2001–2005) [26,32,33,39]. Figure 42.2 provides a summary of the human–machine ergonomics research fields in China during 2001–2005. It can be seen from Figure 42.2 that in those 5 years, research in ergonomics management and administration constituted the largest proportion (15.97%) in ergonomics research work followed by research in occupation and employee’s qualifications (14.78%). Based on these research results, employee’s health standards and job selection criteria were established. The amount of research done on working environment (12.39%) and human– machine system (10.55%) was very close, which indicates that the human comfort during work and relationship between human and machine—human–machine interface—draw increasingly more attention. Human error and system safety (12.14%) also got some 160 140 Qty of treatises

120 100 80 60 40 20 0

1994

1995

1996

1997

1998

1999

2000

2001

2002

Year

FIGURE 42.1  Cronicle summary of ergonomics application research treatises.

2003

Current Status of the Ergonomics Research in China    ◾    1115  

Human–computer interaction system Human research Ergonomics of org. and admin Ergonomics in advanced technology Occupation and employee qualification Research of working environment Cognitive ergonomics Work environment Work load and fatigue Human error and system safety Product design and evaluation

FIGURE 42.2  Proportions of the research fields of ergonomics in China.

attention especially in the area of traffic accidents and production system safety guards. Workload and fatigue, product design and evaluation, and work method and workplace improvement made up a small portion. At present, among the existing ergonomics standards in China, most of them are qualitative guidelines. This situation cannot meet the practical needs of ergonomics for product design and production. For example, the existing ergonomic design requirement database defines only the general product design window. It does not define in detail the comfort zone, work zone, and endurance zone. In the future, design standards about the human body’s work capability need to be created. This is an essential input for a product design. At present, in China, there are no ergonomic assessment standards. The gaps include a process to define the technical procedures and methods for ergonomic assessment and a method for selecting ergonomic assessment subjects. To fill those gaps, it is necessary to establish ergonomics assessment technical standards. In terms of the actual application of occupational ergonomics in China, the research results from automobile, worker safety, and military material and equipment have made a significant impact on the development of science and technology as well as the advancement of society. Although China conducted fundamental occupational ergonomics theory research and also established and implemented standards according to the research findings, the majority of the contents of ergonomics have been limited to physical factors until recently. There is a need to expand the depth and breadth of ergonomics research. There is also a need to balance between theoretical research and actual application of occupational ergonomics. Although ergonomics started late in China, it is developing fast. As science and technology and economy of China develop, expectation of good working conditions and high quality of living will gradually increase. People will pay increasingly more attention to the ergonomic aspects of products. At present, among the various products in the market,

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most products are designed to meet humanistic demands. Although ergonomics has very high application potential in China, it is not quite popular yet and many people still do not understand it. More work needs to be done for research, education, and promotion to increase its popularity.

REFERENCES 1. S. Z. Zhang and S. Wang, Ergonomics in China, Sino-Japanese Medical Conference: Occupational Hygiene Seminars, China Preventive Medicine Association, Tianjin, 1990, pp. 120–122. 2. C. Qi, A brief history of development of human engineering, Human Engineering, Chen Du, Ed., Science-Technology Publishing House of Sichuan, Sichuan, China, 1988, p. 11. 3. S. Wang, L. Li, and J. J. Liu, Biomechanics analysis on waist of sitting work, Chinese Journal of Industrial Hygiene and Occupational Diseases, 13(1):29–31 (1994). 4. L. Li, S. Wang et al., Epidemiological study and ergonomical evaluation of lower back pain in sedentary workers, Industrial Health and Occupational Diseases, 21(1):4–7 (1995). 5. Z. Q. Ding, Current research status and prospect of biomechanics ergonomics and its effects, Chinese Ergonomics, 1(2):62–64 (1995). 6. L. H. He, S. Wang et al., Neck-shoulder-wrist injury of sedentary workers, Chinese Journal of Industrial Hygiene and Occupational Diseases, 8(6):337–339 (1995). 7. W. Sun Wei, D. P. Zhang, and S. Wang, Ergonomics study of manual material handling, Railway Occupational Safety, Health, and Environment Protection, 3(4):246–249 (1995). 8. L. H. He, S. Wang et al., Electromyographic study of neck, shoulder, and wrist of sitting working posture, Railway Occupational Safety, Health, and Environment Protection, 11(2):26–28 (1996). 9. Y. T. Niu, S. Wang et al., Field and simulation studies on low back fatigue in sedentary workers, Chinese Journal of Industrial Medicine, 10(3):145–148 (1997). 10. L. H. He, S. Wang, E. M. Huang et al., Epidemiological investigation on musculoskeletal injury in electronic industry, Chinese Ergonomics, 4(4):12–14 (1998). 11. J. J. Liu, D. X. Wu, Y. R. Xu, L. H. He, and S. Wang, An epidemiological investigation on musculoskeletal injury in sedentary workers, Practical Preventive Medicine, 5(6):331–332 (1998). 12. Q. Zheng, S. Wang et al., Epidemiological investigation of musculoskeletal injury in manufacturing workers, Chinese Ergonomics, 7(2):28–29 (1997). 13. P. Zheng, Z. H. Song, and Y. M. Zhou, Study and developing status and trend on detecting and evaluating techniques of motor driver fatigue, Journal of China Agricultural University, 6(6):101–105 (2001). 14. S. Wang and K. Zhang, Occupational Ergonomics, Tianjin Science and Technology Press, Tianjin, China, 2001. 15. L. H. He, S. Wang et al., The effects of static load on mitochondria function in rabbit muscle, China Occupational Medicine, 28(2):2–4 (2001). 16. S. Wang, L. H. He et al., Changes in energy metabolism of static load-induced muscle injury, Chinese Journal of Industrial Hygiene and Occupational Diseases, 19(3):172–174 (2001). 17. X. M. Xiao, G. H. Bi et al., Review of foreign ergonomics studies and standards, Defense Science and Technology Industry Standardized Research Center GF Report, Beijing, 6–32 (2002). 18. H. Yu, S. X. Hou, L. H. He, and S. Wang, Lower back pain in truck drivers working in plateau areas and its prevention, Chinese Journal of Industrial Hygiene and Occupational Diseases, 20(1):1–3 (2002). 19. S. X. Hou, H. Yu, L. H. He, and S. Wang, A epidemiological investigation on low back pain of truck driver in plateau, Chinese Journal of Clinical Rehabilitation, 6(10):1460–1462 (2002). 20. H. Y. Liang, W. W. Wu, S. Wang, and L. H. He, A monitoring study of electromyography median frequency on fatigue of erector spinalis in drivers working at high altitude, Chinese Journal of Industrial Hygiene and Occupational Diseases, 20(6):461–464 (2002).

Current Status of the Ergonomics Research in China    ◾    1117   21. S. Wang, L. H. He et al., An observation on infrared thermograph of lower back pain patients, Industrial Health and Occupational Diseases, 29(1):39–41 (2003). 22. Q. Y. Yu and J. F. Yu, Logistic regression analysis of nursing staff chronic MSDs’ risk factors, Acta Universitatis Medicinal Anhui, 38(3):240–241 (2003). 23. L. H. He, S. Wang et al., Effect of lumbar protective belt on prevention of low back fatigue in personnel during simulated driving, Chinese Journal of Industrial Hygiene and Occupational Diseases, 4(4):18–20 (2004). 24. G. Z. Li, S. Wang, and X. Feng, Protective effect of vitamin C on muscle strain injury-induced peroxidative damage on rats, Chinese Journal of Industrial Hygiene and Occupational Diseases, 22(4):283–285 (2004). 25. J. Chen, Z. L. Wang, and L. Yang, Analysis of surface electromyography on repetitive lifting task induced fatigue of back muscles, Chinese Journal of Industrial Hygiene and Occupational Diseases, 22(6):402–405 (2004). 26. Z. W. Xie and C. Wu, Research developments on ergonomics application in China in recent ten years, Industrial Safety and Environmental Protection, 31(3):52–54 (2005). 27. L. H. He, S. Wang, and K. P. Ye, Levels of serum creatine kinase, lactate dehydrogenase and their iso-enzymes in low back pain patients, Industrial Health and Occupational Diseases, 31(1): 15–17 (2005). 28. H. C. He, The research progresses on human engineering and its standardization, Technology Foundation of National Defence, (9):5–8 (2005). 29. L. H. He and S. Wang, The investigation of work seat in some industry, Chinese Ergonomics, 11(6):37–39 (2005). 30. Z. H. Zhang, A Research Method for Driving Fatigue Based on Physiological Signal and Its Application, Harbin Industrial University, Heilongjiang, China, 2006. 31. L. Zhang, H. N. Zhang et al., Investigation on occupational muscular-skeletal disorder in three types of occupations, Journal of Public Health and Preventive Medicine, 17(2):74–75 (2006). 32. F. Guo, Y. L. Sun, and Q. H. Ye, Comparative analysis on domestic and overseas ergonomics research, Industrial Engineering and Management, (6):118–122 (2007). 33. P. P. Pau and X. W. Wu, Apply self-organizing map test mining algorithm to analyze Chinese ergonomics research area, Chinese Ergonomics, 13(1):17–20 (2007). 34. T. Y. Jin, Occupational Health and Occupational Medicine, (6th edn.), People’s Medical Publishing House, Beijing, China, 2008, pp. 59–73. 35. Q. X. Zhou, H. Xiao, and X. Zhang, Review on China ergonomic standardization system research, World Standardization & Quality Management, 5(5):13–16 (2008). 36. L. H. He, G. Z. Li et al., Experimental study on the animal model of musculoskeletal strain injury, Industrial Health and Occupational Diseases, (2008). 37. W. D. Liu and Z. X. Wang, Musculoskeletal disorders and ergonomics, Journal of Environmental and Occupational Medicine, 25(6):605–607 (2008). 38. L. Yang, S. F. Yu et al., Occupational musculoskeletal disorder questionnaire, Industrial Health and Occupational Diseases, 35(1):25–31 (2009). 39. R. F. Shen, Reflections of ergonomics and Chinese ergonomics society, Chinese Ergonomics, 152:12–13 (2009). 40. Z. L. Wang, J. J. Li, and L. Yang, Experimental study on assessment of manual lifting techniques by surface electromyography and electrocardiography, Industrial Health and Occupational Diseases, 35(2):69–73 (2009). 41. S. S. Wu, L. H. He et al., Health survey of airport visual display terminal operators, Industrial Health and Occupational Diseases, (2010). 42. China National Institute of Standardization, Fundamental Standardization. http://www.cnis. gov.cn (accessed August, 2010).

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Overview of Ergonomic Needs and Research in Taiwan Chi-Yuang Yu and Eric Min-yang Wang CONTENTS 43.1 Historical Review 43.2 Ergonomics Education in Taiwan 43.3 Ergonomics Society of Taiwan ROC 43.4 Research Projects and Future Development 43.4.1 Research Projects Funded by NSC 43.4.1.1 Taiwanese Static Anthropometric Data Bank 43.4.1.2 Ergonomics Research for Chinese Computer Keyboard Operations 43.4.1.3 Driver Visibility and Safety for Motor Vehicle Design 43.4.1.4 Ergonomics in a Nuclear Power Station 43.4.2 Research Projects Funded by IOSH 43.4.2.1 Development of a High-Mobility Industrial Chair 43.4.2.2 Computerized Manual Materials Handling Assessment System 43.4.3 Future Development 43.5 Conclusions References

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43.1 HISTORICAL REVIEW Ergonomics was first introduced to Taiwan in the early 1960s by industrial designers. In 1962, the Chinese Productivity Center (an affiliate agency of the Ministry of Economic Affairs) sponsored a series of introductory industrial design training courses that were aimed at the promotion of the design of industrial products. During these courses, “human engineering” was presented by Professor Ohara Zirou of Ciba University in Japan. A course in human engineering was taught for the first time 3 years later in the industrial design department of Ming-Chi Institute of Technology in Taipei. Within a decade, many universities, colleges, and junior colleges followed this new trend, offering human engineering courses in their industrial design departments. The term human engineering was 1119

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increasingly heard by many people through commercials in the media. However, most people had only a vague impression of ergonomics, which was considered to be the knowledge of fitting products (e.g., cars and chairs) to the physical dimensions of human beings. Ergonomics has grown rapidly in Taiwan since 1983, becoming increasingly important since the initiation of the course in industrial engineering departments. The industrial engineering department at National Tsing Hua University (NTHU) in Hsinchu was one of the pioneers in offering this course. The course was titled “human factors,” as in the United States, where a majority of the faculty members had received their graduate degrees. The first ergonomics graduate program in Taiwan was initiated a couple of years later at NTHU. Many other universities and colleges followed suit. More than 20 schools currently offer at least one human factors course for undergraduate studies. Human factors has become an important branch in the field of industrial engineering and is increasingly known for its many applications, for example, workplace and protective equipment design, traffic and transportation system design, and control room design for nuclear power plants and chemical plants. Two governmental agencies, the National Science Council (NSC) and the Council of Labor Affairs (CLA), have devoted a substantial amount of energy over the past several years to supporting the promotion of ergonomics. In 1985, NSC invited ergonomics professors from a number of disciplines, for example, industrial design, industrial engineering, and psychology, to discuss and plan the future development of ergonomics in Taiwan. Those meetings concluded with a directive plan, which was then adopted by the NSC as a guideline to grant research projects thereafter. In a different approach, CLA, focusing its efforts on the welfare of laborers, has devoted much of its efforts to promoting ergonomics in the industrial sector for practical purposes. In recent years, CLA has sponsored many introductory seminars for its employees and industrial safety and health personnel. In 1992, the council established the Institute for Occupational Safety and Health (IOSH), one of whose primary missions involves promoting ergonomics research that would lead to the establishment of safety and hygiene standards for the entire nation. This mission is having a significant and positive impact for the future development of ergonomics in Taiwan.

43.2 ERGONOMICS EDUCATION IN TAIWAN Ergonomics courses in Taiwan have primarily been taught in the departments of industrial design and industrial engineering in universities and colleges. For industrial design departments, 6 universities and 20 junior colleges offer ergonomics courses that stress design applications; therefore, anthropometry and biomechanics seem to be the core. Among these universities, two have master’s programs in ergonomics. The educational backgrounds of those faculty members are industrial design, industrial engineering, psychology, or related areas. For industrial engineering departments, 5 universities and 20 junior colleges have general ergonomics courses, and of these, 3 universities currently offer doctoral and master’s programs. The educational backgrounds of those faculty members are mainly ergonomics, industrial engineering, and psychology. Ergonomics education in the industrial engineering departments is more diversified and in depth

Overview of Ergonomic Needs and Research in Taiwan    ◾    1121   TABLE 43.1  Ergonomics Education Programs in Universities in Taiwan as of 1993

Faculty Doctoral students Master’s students Undergraduate courses

Postgraduate courses

National Tsing Hua University

National Chiao Tung University

National Taiwan Institute of Technology

4 5 13 Psychology Work study Human factors 1 Human factors 2 Industrial safety Human performance Work physiology Environmental analysis Human-machine system Human-computer interface Industrial safety Safety engineering Biomechanics Vision and eye physiology Color science Design evaluation

3 4 5 Motion and time study Human factors Industrial safety and hygiene Industrial organization psychology

4 9 10 Industrial psychology Human factors Industrial safety Consumer behavior Time and motion study Biomechanics Fundamental physiology Fundamental psychology Advanced human factors Cognition Human reliability Human-machine system

Human information process Advanced human factors Measurement and evaluation of human performance Human performance Human and computer Human-machine system Problem solving

than that in industrial design departments. The numbers of faculty members and students along with the titles of the ergonomics courses of the three universities that offer doctoral programs are listed in Table 43.1.

43.3 ERGONOMICS SOCIETY OF TAIWAN ROC The Ergonomics Society of Taiwan ROC (EST) was founded in February 1993, with the stated objectives of promoting indigenous research and technological applications as well as encouraging international cooperation and exchange in ergonomics. The EST’s executive council tentatively planned to hold one national conference and publish at least one journal each year and also to occasionally sponsor international symposiums. The EST also coordinates research projects and provides training programs for interested parties, such as IOSH and those in the industrial sector. The EST is an independent organization. However, it closely coordinates with local institutes of industrial engineering and the Industrial Design Society for their common interests. The society had roughly 180 individual members and seven organizational chapters by the end of 1993. In terms of educational background, industrial engineering is the largest group and industrial design the second largest (see Figure 43.1). In terms of occupations, university and college faculty are the largest group, with students being second (see Figure 43.2). Three of the seven organizational chapters are governmental institutions, that is, IOSH, Taiwan Power Company, and the Center for Industrial Safety and Health Technology at the Industrial Technology Research Institute; the remaining four are colleges. The officers

1122    ◾    Occupational Ergonomics: Theory and Applications Industrial education Chemistry 2% Psychology 3% 3% Industrial safety 3%

Mechanical engineering 2%

Management science 6% Industrial design 10% Industrial engineering 57% Others 14%

FIGURE 43.1  Educational backgrounds of EST’s 180 members as of 1993. Research scientist 8%

Others 2%

Private industry 10%

Faculty member 51%

Student 29%

FIGURE 43.2  Classification of EST members’ occupations as of 1993.

of EST are striving diligently to promote their society in all sectors of Taiwan. It is hoped that more individual members will be enrolled from among nonacademic professionals and that more organizational chapters will be formed in the private sector. Less than 6 months after its formation, the society had already sponsored an industrial ergonomics and safety workshop and had also conducted a domestic ergonomics

Overview of Ergonomic Needs and Research in Taiwan    ◾    1123  

manpower survey. On its first anniversary, an international conference on ergonomics and occupational safety and health was held. Around 200 local researchers and practitioners as well as many from Japan and the United States participated. The society is currently coordinating an ergonomic industrial chair development and evaluation research project. The prototype of the chair is presently in the mass production stage and will be released to industry for a large-scale user test within months. Several other nationwide ergonomics projects—for example, anthropometric, biomechanical, craniofacial, and work physiological databases for the domestic population—are also in the planning stage. These databases are expected to be completed within the next 6 years. In addition, the society is tentatively planning to place an emphasis on promoting ergonomics to the public in the coming years. Among others, one of the most effective approaches involves presenting introductory films and publishing articles for the mass media, for example, public television programs and newspapers.

43.4 RESEARCH PROJECTS AND FUTURE DEVELOPMENT 43.4.1 Research Projects Funded by NSC Previous ergonomics research was primarily funded by NSC; however, several research projects have recently been funded by other governmental agencies, such as CLA and the Ministry of Transportation. Since 1985, NSC has given grants to more than 70 ergonomics-related research projects, and the total budget has exceeded US $8 million. As ergonomics-related research was comparatively new to NSC, the funded research projects were of small scale and not integrated. Among those projects, some important ones are listed in the following. 43.4.1.1  Taiwanese Static Anthropometric Data Bank The primary purpose of this study focused on establishing a static anthropometric data bank for Chinese residents in Taiwan using a computerized photographic method [1]. Stratified random sampling was applied to determining the sampling site; in addition, a sample size was established by considering standard errors in a pilot study. A photographic method was next employed in addition to direct measurement of selected body dimensions. A cumulative total of 933 subjects were measured. The data were entered from photos via a digitizing tablet into a microcomputer for processing. The resulting anthropometric data bank was established, and recommendations were presented for future research efforts. 43.4.1.2  Ergonomics Research for Chinese Computer Keyboard Operations The primary purpose of this research effort [2] involved developing ergonomic design guidelines for a Chinese computer keyboard. Some of the subproject titles translate as follows:

1. A questionnaire survey on Chinese VDT keyboard operation behaviors and the causes of discomfort 2. The anthropometry of hands for computer keyboard design

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3. A study of the key grouping and layout for computer keyboard design 4. A study of finger movements in keyboard operation 5. A study of table-chair height and arm-shoulder postures in keyboard operation at a VDT workstation 6. A study on readability and legibility of Chinese VDT key legends

7. A study of keyboard design for the domestic population

43.4.1.3  Driver Visibility and Safety for Motor Vehicle Design The primary purpose of this research effort focused on developing ergonomic design guidelines for cars and motorcycles by emphasizing driver visibility and safety. This project consisted of five subprojects:

1. A questionnaire survey on driver comfort and safety for heavy and light motorcycles 2. A study of the drivers’ visual field, dark perception, and signal response time 3. An ergonomic study of motorcycle helmet design 4. The effects of tail light sizes on daytime braking reaction time for motorcycles 5. An evaluation of driving effectiveness on tail light configurations and the visual interference between dashboard displays and the steering wheel 43.4.1.4  Ergonomics in a Nuclear Power Station This research effort was composed of a series of projects concerning supervisory control, error diagnosis, and problem solving for nuclear power stations. The research projects included

1. Application of queuing theory to quantify information workload in supervisory control systems [3] 2. Stochastic modeling of human errors on system reliability [4] 3. Dynamic hierarchical modeling of problem solving [5] 4. The prevention of human errors in nuclear power plant maintainability through root cause analysis [6] 5. The design strategies of Chinese information display in supervisory control systems [7] 43.4.2 Research Projects Funded by IOSH Other than NSC, IOSH has funded several research projects during the past few years. Among these projects, two are especially important, the development of a high-mobility industrial chair and a computerized manual materials handling assessment system.

Overview of Ergonomic Needs and Research in Taiwan    ◾    1125  

43.4.2.1  Development of a High-Mobility Industrial Chair An anthropometric measurement procedure [8] was developed for investigating the design parameters for a low sit-stand posture, and the data on these parameters were applied to designing a chair for high-mobility industrial tasks. The anthropometric procedure used ischial tuberosities as the seat reference point. Investigating the design parameters required tracing spinal curves of five postures and a posterior thigh curve via a three-dimensional (3D) curve-tracing device. The high-mobility chair was designed with a special seat pan and backrest profiles to accommodate the musculoskeletal geometrical configuration of a low sit-stand posture. The seat pan consists of pelvic support that supports the ischial tuberosities and the areas behind them and a thigh support that maintains the thighs at a 15° inclination angle, resulting in a 105° torso-tothigh angle. The backrest consists of a lumbar support that preserves lumbar lordosis and a thoracic support that supports the upper back during backward leaning. 43.4.2.2  Computerized Manual Materials Handling Assessment System The primary purpose of the second project [9] was to develop an automated computer system for evaluating the risk of low back injuries that occur in manual materials handling. The system employs a computer vision technique to assess postures while a worker is performing manual materials handling tasks. Based on one of the six biomechanical models available, for example, Chaffin’s [10], the system can calculate the strain produced in the lower back and some joints on the basis of anthropometric data. The calculated strain values are then compared with the corresponding predicted injury load, indicating the worst posture to take during the job cycle. Recommendations for correct manual materials handling posture are finally provided.

43.4.3 Future Development The NSC funded a research project in 1990 to plan ergonomics development for 5 years. The ergonomics research topics suggested by local researchers are summarized in the following text. This summary includes many of the most essential aspects in this field (excluding military applications), which indicates the enormous requirements and potential areas for ergonomics research. 1. Occupational safety and industrial ergonomics

a. Design and evaluation of traffic signs and symbols



b. Human factors applications in product design



c. Measurement and standards for workplace environments



d. Computerized biomechanical evaluation for manual materials handling



e. The effects of workplace environment quality on work performance

2. Anthropometry, biomechanics, and work physiology

a. Structural and functional anthropometric database of Taiwanese adults



b. Physical strength data for Taiwanese

1126    ◾    Occupational Ergonomics: Theory and Applications



c. Standards for physical work



d. Epidemiological study of occupational musculoskeletal disorders

3. Human information processing and decision behaviors

a. Error detecting and diagnostic behaviors



b. Behavioral models of human errors



c. Problem-solving behavior model and its applications in automated systems



d. Human factors standards for the design of a knowledge-based information system



e. The theory and applications of mental models



f. The application of human decision-making behavior theory in a decision support system

In addition, IOSH has drawn up a 6 year ergonomics research plan that is aimed specifically at establishing a variety of work guidelines and standards for various tasks. The plan has been classified as a long-term directive plan in Executive Yuan (the highest public administration organization in Taiwan). The plan involves establishing indigenous anthropometric, strength, and work physiology databases for enhancing occupational safety and hygiene in the workplace. The main ideas are listed in the following. Anthropometric databases: This project will consist of establishing static and dynamic databases for domestic workers. For static measurements, about 300 body dimensions will be measured from 3200 adult subjects. Stratified random sampling on gender, age, and other variables will be employed on the basis of the national demographic data. For dynamic measurement, more than 50 ranges of motion for specific postures will be measured from the same subjects. This project, with its estimated budget of approximately US $1,200,000, will be initiated in 1994 and reach completion in 1996. A mobile measurement laboratory is proposed, and more than 30 investigators will participate in this project at three measurement centers stationed in major universities nationwide. Specific results of this project will consist of static and dynamic anthropometric databases. Three-dimensional (3D) and two-dimensional (2D) manikins will be made according to the actual data. Craniofacial anthropometric database: The purpose of this project involves establishing a head and face anthropometric database for Taiwanese workers as well as constructing a set of 3D head and face models for various applications such as respiratory protective equipment. It is planned to have about 1000 subjects drawn by stratified random sampling on gender, occupation, age, and area based on national demographic data. The data will then be categorized, by considering the facial length, facial width, and standard deviations, into several groups, and a “typical model” will be recommended for each group. This project started in 1993 and will be ended in 1995. The estimated budget for this project is about US $200,000. It is expected to yield a craniofacial anthropometric database and a complete set of typical 3D craniofacial models.

Overview of Ergonomic Needs and Research in Taiwan    ◾    1127  

Strength database: The primary purpose of this project involves collecting basic strength data for various biomechanical applications as well as paving the way for establishing physical work standards. These data will be collected along with anthropometric measurement by the same group of researchers. The strength measurements will include lifting, pushing, pulling, carrying, gripping, and gripping torque. The data will be tabulated according to strength and torque moment with respect to specific conditions both isometrically and isotonically. Roughly 1000 subjects will be randomly selected from those of the anthropometric database project and measured for this purpose. Work physiology database: The primary purpose of this project is to collect physiological work data for setting up physiological work standards. These data will include maximal aerobic power, oxygen uptake at various workload levels, respiratory rate, pulmonary ventilation capacity, and similar information. This project is still in its planning stage.

43.5 CONCLUSIONS A significant amount of progress in ergonomics education and research has been achieved in Taiwan over recent decades. Ergonomics education is currently progressing at a good pace in terms of both quantity and quality. The EST, founded in 1993, will play an important role in promoting future research, education, and international exchange in the global village of ergonomics. Ergonomics research is gradually becoming solid and integrated, especially since the establishment of IOSH. Much faster growth is foreseeable in Taiwan over the next decade.

REFERENCES 1. C.-C. Li, S.-L. Hwang, and M.-Y. Wang, Static anthropometry of civilian Chinese in Taiwan using computer-analyzed photography, Hum. Factors 32:359 (1990). 2. L. F. Chen, F. K. Wu, S. S. Lai, M. C. Lin, K. S. Chen, M. J. Suon, and S. S. Kuan, The human factors studies on computer keyboards (Proj. NSC75-0415-E006-02), 1987. (In Chinese, available from National Science Council, Taipei, Taiwan, ROC.) 3. C.-C. Her and S.-L. Hwang, Application of queuing theory to quantify information workload in supervisory control systems, Int. J. Ind. Ergon. 4:55 (1989). 4. C.-T. Hwang and S.-L. Hwang, A stochastic model of human errors on system reliability, Reliab. Eng. Sys. Safe. 27(2):139–153 (1990). 5. C.-H. Wang and S.-L. Hwang, The dynamic hierarchical model of problem solving, IEEE Trans. Sys. Man. Cybern. 19:946 (1989). 6. T.-M. Wu and S. L. Hwang, The prevention of human errors in nuclear power plant maintainability through root cause analysis, Appl. Ergon. 20:115 (1989). 7. S.-L. Hwang, M.-Y. Wang, C.-C. Her, D.-M. Wu, and C.-D. Hwang, The design strategies of Chinese information display in supervisory control systems, Int. J. Hum. Comput. Interac. 2:41 (1990). 8. C. Y. Yu, K. K. Li, and Y. P. Chen, Development of a high mobility industrial chair (Proj. IOSH82-H124), 1993. (In Chinese, available from Institute for Occupational Safety and Health, Council of Labor Affairs, Taipei, Taiwan, ROC.) 9. M. J. Wang and K. J. Hwang, Computerized manual material handling assessment system (Proj. IOSH82-H121), 1993. (In Chinese, available from Institute for Occupational Safety and Health, Council of Labor Affairs, Taipei, Taiwan, ROC.) 10. D. B. Chaffin, Biomechanical modeling of the low back during load lifting, Ergonomics 32: 685 (1988).

Chapter

44

Overview of Ergonomics in Australia Jean Mangharam CONTENTS 44.1 Introduction 44.2 Historical Background and Significance of Occupational Ergonomics 44.2.1 Demographics 44.2.2 Ergonomics Profession 44.2.3 Certification and Competencies 44.3 Legislation and Government Activity 44.3.1 Occupational Safety and Health Legislation 44.3.2 National Harmonization 44.3.3 Manual Tasks Legislation 44.3.4 Safe Work Australia 44.3.4.1 Hazard Exposure Research 44.3.5 Heads of Workplace Safety Authorities 44.3.5.1 Design 4 Health Manual Handling 44.3.5.2 Safe Steps: Manual Handling and Slips, Trips, and Falls in Hospitals 44.3.5.3 National Falls from Heights in the Heavy Vehicle Sector Campaign Final Report 44.3.5.4 Prevention of Falls in Construction 44.3.5.5 Manual Handling in Manufacturing 44.3.6 Jurisdictional Activity 44.4 Ergonomics Research 44.4.1 Early Research 44.4.2 Recent Research 44.4.2.1 Musculoskeletal Disorders 44.4.2.2 Health-Care Ergonomics 44.4.2.3 Mining 44.4.2.4 Transport 44.4.2.5 Agriculture

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44.4.2.6 Slips, Trips, and Falls 44.4.2.7 Anthropometry 44.4.2.8 Human–Computer Interaction 44.4.2.9 Product Design 44.4.2.10 Human Motor Skill 44.4.2.11 Job Demands 44.4.2.12 Cost-Benefit Analysis 44.5 Applied Ergonomics and Case Studies 44.6 Ergonomics Training Programs 44.7 Emerging Issues 44.8 Study Questions Acknowledgments References

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44.1 INTRODUCTION Interest in the field of ergonomics in Australia today is healthy, and it continues to develop within the realms of research, applied ergonomics, and public policy. There is activity within all three domains of ergonomics, including the physical, cognitive, and organizational domains. However, striking a balance between the application of ergonomics in all domains remains a challenge, as the interpretation of what “ergonomics” is by the Australian public remains inconsistent and the need to increase the awareness of its full potential and value is still needed (Caple 2008). Although acceptance of the application of “ergonomics” across industries has improved since the 1960s and there is evidence that there has been some consolidation of past and present work that has been translated into public policy by peak bodies, cost benefit analysis and rigorous field trials are still lacking in numbers and there remains a plea by ergonomists to maintain the quality of observation, especially for translation into public health policy, as it has been suggested that ergonomics owes much of its past success to this trait, as displayed by its pioneers (Welford 1976). Maintaining the level of specialization we have seen in Australia hitherto may also pose a challenge in the future as the number of universities that offer postgraduate diplomas and degrees in human factors and ergonomics in Australia has reduced over the past 10 years. Paralleling this are emerging issues faced by the Australian society, not dissimilar to those faced by other developed countries, all of which add further dynamics to the already present challenges.

44.2 HISTORICAL BACKGROUND AND SIGNIFICANCE OF OCCUPATIONAL ERGONOMICS 44.2.1 Demographics Australia is a federation, with six states and two internal territories including the Australian Capital Territory (ACT), New South Wales (NSW), Victoria (Vic), Queensland (Qld), Western Australia (WA), South Australia (SA), Northern Territory (NT), and Tasmania (Tas). Much of the interior of the country is sparsely populated, and the bulk of the population lives on the east coast of the country (NSW, Vic, Qld, ACT). In 2009, the country had a population of

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approximately 22 million (Australian Bureau of Statistics 2009a). It is projected to increase to between 30.9 and 42.5 million people by 2056, and to between 33.7 and 62.2 million people by 2101. It has been projected that a large percentage of population growth will be owed to overseas migration. The ageing of Australia’s population, already evident in the current age structure, is expected to continue. This is the result of sustained low levels of fertility combined with increasing life expectancy at birth (Australian Bureau of Statistics 2008). In 2008–2009, 11 million people were employed across all industries. From an industry perspective, the retail trade industry employed the greatest number of people (1.2 million employed persons or 11% of total employment). Health care and social assistance employed 1.1 million people (just under 11% of total employment) followed by manufacturing and construction (both 9%), and education and professional, scientific, and technical services (both 7%). These industries were also the main employing industries in 1998–1999, although retail trade has displaced manufacturing as the largest employer (Australian Bureau of Statistics 2010). Of all employed persons in October 2009, 54% were made up of males (5,883,900 males employed), contributing to 932 million aggregated hours worked in the month of October 2009. Although almost half of the workforce (46%) is made up of female workers (4,924,000 female employed), females contribute to less hours worked at 38% of time worked by all employed Australians (587 million aggregated hours worked) (Australian Bureau of Statistics 2009b). 44.2.2 Ergonomics Profession Activities that can be described as ergonomics in nature commenced in Australia in the late 1930s (Howie and Macdonald et al. 1988). The work was largely concerned with human factors in relation to flying. Following this, ergonomics research groups were established in government departments and universities. Ergonomics practice and its profile dramatically increased and altered during the 1980s as new occupational safety and health (OSH) legislation was introduced and an “epidemic” of work-related repetitive strain injury (RSI) was experienced in Australia. The profession has progressed in various realms since that period, and its involvement in the international ergonomics scene through formal engagement, such as through the International Ergonomics Association (IEA), and multinational collaborative projects has become significant. Today, the Human Factors and Ergonomics Society of Australia (HFESA) is the professional organization for ergonomists and human factors specialists working in Australia, having representation from many disciplines. The HFESA was established in 1964 as the Ergonomics Society of Australia and New Zealand (ESANZ), arising from a conference held in Adelaide, South Australia (Welford 1976; Howie and Macdonald et al. 1988). In 1986, separate ergonomics societies for New Zealand and Australia (New Zealand Ergonomics Society and the Ergonomics Society of Australia) were formed. The society was renamed HFESA in 2003 to reflect its broad scope of interests and contributions (Bullock 2001). The HFESA has branches in each state and territory which report to the national committee. The society’s activities are directed by its strategic plan, the responsibilities for which are shared by branches. An annual national conference, regular newsletters, and state-run workshops and talks provide a means of communication for members. Several special interest groups exist to offer a focus for specialist fields including the Anthropometry Resource

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Australia Special Interest Group (ARASIG), Computer-Human Interaction Special Interest Group (CHISIG), Rail Human Factors group (RAILSIG), and Health care Ergonomics group. There are various levels of membership that may be obtained by an individual with HFESA, including certified professional ergonomist (CPE), full member, affiliate, and student membership. All CPEs and full members of the HFESA must follow the HFESA code of practice to retain membership (Human Factors and Ergonomics Society of Australia 2009a). A national professional development committee was developed in 2007, and the HFESA annually appoints a national professional development officer to coordinate the program across the country. Professional development is considered to include activities which increase the human factors and ergonomics competencies of members, or otherwise enhance members’ capacity to contribute to the aims of the society (Human Factors and Ergonomics Society of Australia 2009b). The HFESA is a federated society of the IEA, having been admitted by the council for having met and continuing to fulfill the eligibility criteria provided by the IEA rules (International Ergonomics Association 2009). Professional ergonomists from Australia have taken a leadership role at the international level including David Caple being the 17th President (2006–2009) and their contributions to this field have been recognised being recipients of IEA Liberty Mutual Research Award in 2008 (Andrew Shaw, Verna Blewett, Laurie Stiller, Christine Aickin, Drew Dawson, Sally Ferguson, Stephen Cox, Kaj Frick) and in 1999 (Shirley Ann Gibbs). Many Australian ergonomists are also active in the IEA technical committees. 44.2.3 Certification and Competencies The need for a certification system and the criteria which could be used to certify professionally qualified ergonomists in Australia created debate when it was first raised in the society. In 1985, a proposal to proceed with developing a professional certification scheme was adopted by the society. In 1990, 21 society members were awarded professional certification status at the first ceremony of its kind in Australia. The Professional Affairs Board remains active in updating its criteria for membership. In 1990, the Australian government moved to introduce competency based assessment in all occupations and professions. It was realized that a list of ergonomics competencies was vital for the certification and recertification procedures and as a resource in planning and accrediting education programs. Subsequently, the Ergonomics Society of Australia (ESA) defined and published its own outline of core competencies for an ergonomist. Professor Margaret Bullock had a major role to play in this development, as she was also leading an international IEA task force to outline international competency standards for a practicing ergonomist (Bullock 2001). Currently to become a CPE in the HFESA, the applicant must demonstrate that they have the following: • Been an active member of the HFESA or other IEA affiliated society for the past 2 years • Completed an education program which provides a comprehensive set of ergonomics competencies

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• Expertise in ergonomics demonstrated through the provision of at least one major work sample, supported by one or more work samples or products of smaller magnitude • A minimum of 4 years of full-time practice in human factors and ergonomics or the part-time equivalent (Human Factors and Ergonomics Society of Australia 2009a)

44.3 LEGISLATION AND GOVERNMENT ACTIVITY 44.3.1 Occupational Safety and Health Legislation The legislative powers of the Australian federal government are set out in the commonwealth constitution. The commonwealth constitution does not give the commonwealth a general power to legislate for occupational health and safety (OHS); hence, there are 10  OHS statutes (6 state acts, 2 territory acts, a commonwealth act covering commonwealth employees and employees of certain licensed corporations, and a commonwealth act covering the maritime industry). There are also specialist OHS statutes covering the mining industry in some states (National Research Centre for OSH Regulation 2009). Historically each Australian state adopted most of the provisions of the nineteenth century British health and safety legislation (particularly the 1878 Factories Act, and later the 1901 Act) so that by 1970 each of the six states had an OHS statute implementing the traditional British model of OHS regulation. OHS laws in Australia were gradually reformed from the 1970s onward, much of which were influenced by the 1972 report chaired by Lord Robens (Robens 1972; Browne 1973). Each of the Australian OHS statutes today adopts the well-known three-tiered approach recommended by the Robens report—broad, overarching general duties and more-detailed provisions in regulations and codes of practice. Provisions in regulations have force of law (they are mandatory), whereas codes contain guidance material, which can be used as evidence in a prosecution for an alleged contravention of an applicable regulation or general duty provision. The general duties generally cover employers, the self-employed, occupiers, designers, manufacturers and suppliers of plant and substances, employees, and some other duty holders in some jurisdictions. They require the duty holder to provide and maintain, as far as is reasonably practicable, a working environment that is safe and without risks to health— although the wording of these provisions differs from jurisdiction to jurisdiction and between duty holders (Johnstone 2004; National Research Centre for OSH Regulation 2009). 44.3.2 National Harmonization Although, OSH legislation in Australia are currently separate for each state and territory, this system is in a state of transition as the Council of Australian Governments (COAG, the peak intergovernmental forum in Australia) initiates, develops, and monitors the implementation of policy reforms that are of national significance and which require cooperative action by Australian governments. All jurisdictions are currently working toward nationally consistent laws. This nationalization process of OSH laws has been termed “harmonization.” It takes on a consultative approach which considers input from multiple stakeholders, including

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representatives each of various jurisdictions, workers, and employers. In 2008, a review panel was established, and a report was released by the panel in 2009 with recommendations from which draft laws will be developed based on existing laws from the various jurisdictions. Nationally harmonized OHS laws and associated regulations are set to commence by December 2011 (Mayman 2009). The development of national OHS laws has been driven by Safe Work Australia, in partnership with the commonwealth, state, and territory governments. The Safe Work Australia Council held its inaugural meeting in June 2009 (Safe Work Australia 2009a). 44.3.3 Manual Tasks Legislation One of the most significant ergonomics-related regulations that exist in all jurisdictions is those written primarily for the prevention of musculoskeletal disorders (MSDs). They have been termed “manual handling” or “manual tasks” regulations. Throughout Australia certain terms are being phased out, and there has been greater acknowledgment of the wide-scope condition MSD. Sprains and strains, body stressing injuries, and occupational overuse syndrome terms are gradually being replaced by the umbrella term MSDs. Manual handling is being replaced by manual tasks, adding a wider scope to the activity so that it encompasses all risk factors associated with MSDs, not just those perceived to be related to handling loads or applying high forces. In 2007, a national standard and a national code of practice for the prevention of MSDs from performing manual tasks at work (Australian Safety and Compensation Council 2007a,b) was developed to replace previous standards and codes which addressed manual handling and occupational overuse syndrome (National Occupational Health and Safety Commission 1994, 2005). All national standards and codes of practice are guidance and advisory documents only, and their implementation is dependent on legislation enacted by state/territory OHS authorities. The code of practice provides practical guidance on the risk management process, particularly for employers. Employers have the duty to identify potential MSD hazards and understand the nature and sources of risk so that they can make informed decisions about what they need to do to eliminate or control them. To manage risk, they are required to 1. Identify hazardous manual tasks by screening work involving manual tasks to recognize those which have the potential to cause MSD 2. Assess risks of MSD that arise from these hazards 3. Eliminate tasks or parts of the task that have a potential to cause MSD, or if this is not reasonably practicable, implement risk controls to minimize the risk of MSD as far as is reasonably practicable 4. Monitor and review the effectiveness of the measures you have implemented This practical guidance document requires duty holders to identify potentially hazardous manual tasks that present with physical risk factors related to adverse force, postures,

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movements, and vibration. As part of the risk assessment process, duty holders are required to identify the risk factors for each hazardous task and determine the source(s) of the risk. The risk assessment section does consider and require duty holders to assess some nonphysical risk factors associated with systems of work, work organization, and work practices (considered to be indirect risk factors). This category includes high workloads and tight deadlines, little latitude for workers to influence workload or work methods, and unsuitable or insufficient resources such as staffing levels, equipment, and guidance available to workers. The document states that if the risk cannot be eliminated by duty holders, the risks should be minimized by altering or redesigning the source of the risk. Physical and nonphysical aspects of the workplace are considered to be potential sources of risks. They include • Design and layout of work area • Nature of the load • Nature of tool, equipment, or item • Work environment • Work organization, work system, or work practice The development of this code and standard has not been without challenges. Debates have centered around multiple aspects of the practical guidance documents including the scope, definitions, duty holders that should be included and their responsibilities, risk factors that should be considered, risk assessment tools to be suggested, and size and complexity of the document. The process to update the national standards and codes relevant to the prevention of MSDs commenced in 2003, and the first draft for public comment was released in 2005. The process was revisited in 2006, and the final documents were endorsed by the Australian Safety and Compensation Council (ASCC) in 2007 for jurisdictions to implement in accordance with their legislation. The adoption of this standard and code by the various jurisdictions across Australia to support their regulations has been poor, with more states still referring to their own regulation and codes of practice (WorkCover Corporation of South Australia 1990; Commission of Occupational Safety and Health of Western Australia 2000; Victorian WorkCover Authority 2000; Workplace Health and Safety Queensland 2000). However, the process of developing a national code of practice will be revisited as the harmonization process progresses. 44.3.4 Safe Work Australia Safe Work Australia is a national health and safety peak body that has seen name and role changes over time. The organization has been known as the National Occupational Health and Safety Council (NOHSC) and ASCC in the past. In November 2009, Safe Work Australia began operating as an independent statutory agency with primary responsibility to improve OHS and workers’ compensation arrangements across Australia. The activities of the agency today include the coordination and development national

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laws, the publication of national standards and codes, and the coordination of research projects that may be applied to OHS policy. Safe Work Australia has published several ergonomics-related research projects in the past few years including • Hazard exposure research (Australian Safety and Compensation Council 2009) (described in the following text) • MSDs—a series of publications to support the work toward the prevention of MSDs commenced in 2003 (Bryan Bottomley and Asscociates 2003a,b; David Caple and Associates Pty Ltd 2003; NOHSC Office Safe Design Team 2003; Uniquest Pty Ltd 2003), and more recent papers which collectively have provided a deeper understanding of the complexity of the risks associated and challenges for setting strategies and policy for the prevention of this condition (Safe Work Australia 2006a,d) • Work-related mental disorders (Safe Work Australia 2006c) • Safe design (Australian Safety and Compensation Council 2006) • The manual handling of bariatric people (Safe Work Australia 2009c) • Overweight and obesity: implications for workplace health and safety and workers’ compensation (Australian Safety and Compensation Council 2008) • Anthropometric data in Australia—refer to emerging issue section for details of this study (Safe Work Australia 2009b) • Ageing workforce (Safe Work Australia 2005) • Work-related fatigue (Safe Work Australia 2006b) 44.3.4.1  Hazard Exposure Research The purpose of the National Hazard Exposure Worker Surveillance Survey was to gather information to guide decision makers in developing prevention initiatives that will ultimately lead to a reduction in occupational disease. The first publication presents research findings from a quantitative research study of 4500 telephone interviews with Australian workers. To find out more about MSD and mental disorders hazard exposures, biomechanical demands and psychosocial working conditions were asked of participants. In relation to biomechanical risk factors, the study showed that across all industries, repetitive arm movement was the most common biomechanical demand, and that tiredness was the most common effect of the biomechanical demands placed on respondents at work. In relation to controls, the study showed that respondents from the manufacturing and mining industries were more likely to report that lifting equipment was provided, compared to respondents from other industries. In relation to psychosocial risk factors, the study showed that across the industries, the most common time demand is the need to work quickly and the most common cognitive

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demand is work needing undivided attention. The majority of respondents reported to have a good working relationship with their work colleagues and felt that their fellow workers provided them with the help and support they needed and were willing to listen to their work-related problems. In terms of “bullying” in the workplace, 632 respondents reported they had experienced it. Most of those who experienced workplace bullying were bullied by their supervisor/manager or their coworkers. In relation to controls, the study showed that antistress and antibullying policies are the main strategies put in place to prevent workers from becoming too stressed; however, a third of workplaces have nothing in place (according to the workers). 44.3.5 Heads of Workplace Safety Authorities The Heads of Workplace Safety Authorities (HWSA) is a group comprising the general managers (or their representatives) of the peak bodies responsible for the regulation and administration of OHS in Australia and New Zealand. The HWSA coordinate national compliance campaigns targeted at specific industries across all jurisdictions. These campaign initiatives support the National OHS Strategy 2002–2012 and facilitate the development of consistent approaches to nationally recognized priorities. Campaigns that have related to the field of ergonomics include the following: 44.3.5.1  Design 4 Health Manual Handling In 2004, a campaign to address manual handling hazards in the Health and Community Services Industry Sector was conducted (Heads of Workplace Safety Authorities 2005). This project was one of the first collaborative campaigns conducted by the Australian OHS agencies. During the campaign, 643 randomly selected workplaces (171 hospitals and 472 aged care facilities) were audited across Australia. Information was obtained from a total of 8 focus groups involving 62 workplace health and safety inspectors and other relevant OHS staff. Findings showed that dramatic improvements occurred in the standard of manual handling risk management within the industry sector over the previous 5 years. The authors reported that these improvements were likely to have been a result of accreditation agency requirements, as well as the activities of the various OHS agencies and the widespread promotion of “no-lift” policies. The project showed that effective OHS management system for manual handling was more likely to be seen in organizations that had the presence of a person in the organization whose responsibilities include OHS. There was strong evidence that workplace-based manual handling safety culture, demonstrated by safety activity, does reduce the level of manual handling task risk at a workplace. Workplaces appeared to have controlled patient-handling risks reasonably well. However, risks remain uncontrolled in other general manual handling areas such as kitchens, food services, and laundries. It was identified that task risk assessments are less frequently undertaken in a systematic manner in nonclinical areas. Design issues relating to the design of buildings, furniture, and equipment which impacted on the uncontrolled manual handling risks were also identified during the task inspections. The design of wheeled equipment such as trolleys was identified as the most common design issue impacting on uncontrolled

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manual handling risk. Issues related to access and space was the second most common design issue, particularly problems relating to storage, space available within rooms, and the width of doors and corridors. 44.3.5.2  Safe Steps: Manual Handling and Slips, Trips, and Falls in Hospitals As a follow-up, the 2004 Design 4 Health Campaign, the Safe Steps—National Hospital Intervention and Compliance Campaign, conducted in 2008, aimed to reduce the number of manual handling and slip and trip injuries sustained by nonclinical (kitchen, launderette, and clinical sterilization) hospital workers (Heads of Workplace Safety Authorities 2008a). A total of 203 audits across the nation were undertaken. Most enforcement actions taken by inspectors (approximately 70%) were related with manual task activities, and the majority of improvement notices issued were associated with Central Sterilization and Supply Department (CSSD) work area. Most hospitals (approximately 70%) were rated as “above compliant” for hazard identification, risk assessment, risk control, purchasing, training, and management commitment. The findings from the project showed that most of the time hospitals are controlling their manual tasks and slips/trips risks. However, it appears that there is some room for improvement for controlling risks in the nonclinical areas assessed, especially CSSDs. Although the audit approach does not allow direct data comparison with the Design 4 Health Campaign, risk identification and control in nonclinical areas were found to be better controlled in 2008 than 2004, and these findings suggest improvement has been made since the last campaign. 44.3.5.3  National Falls from Heights in the Heavy Vehicle Sector Campaign Final Report In late 2003, an HWSA campaign was conducted in the transport industry focusing on falls from heights in the heavy vehicle sector (Heads of Workplace Safety Authorities 2006). The national strategy had two elements, information/advisory and compliance elements. The four primary sectors focused on during the program were car carriers, tankers, dry bulk haulage (pneumatic), and livestock transport. One of the controls that were seen to be implemented as part of the program was the modification of vehicles so that they were fitted with falls prevention systems. A market appeared to have been developed, and suppliers of falls systems retrofitted many vehicles. The true extent of the impact of the program could not be measured; however, a few anecdotal findings reflected positive outcomes. 44.3.5.4  Prevention of Falls in Construction In 2007/2008, “Prevention of Falls in Construction” was conducted as a repeat of a 2003/2004 HWSA joint construction compliance project (Heads of Workplace Safety Authorities 2008b). The two objectives of this campaign were to undertake a coordinated national compliance campaign focusing on falls prevention in the housing construction and the smaller general construction industry sectors, and compare the 2007/2008 level of fall prevention

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compliance with that found in the 2003/2004 campaign. A total of 1044 site inspections occurred and were distributed evenly between regional areas and the capital cities. Of the sites inspected, only 35% were compliant with falls prevention requirements. Compared with 2004, the proportion of enforcement action required was down by 24%. A significant sample of inspectors (104) from across Australia, who were to be involved in the 2008 campaign, undertook a voluntary online inspector survey prior to the field interventions commencing. This survey was used to gain an understanding of inspectors’ perceptions of changes, if any, within the targeted construction sectors since 2004. Only 2% of inspectors believe that there had been deterioration in the use of fall prevention controls, while approximate 75% reported that there had been a slight or obvious improvement. Inspectors indicated that overall the housing subsector had seen the most obvious improvement since 2004. 44.3.5.5  Manual Handling in Manufacturing The primary purpose of this campaign was to improve the capability of employers within targeted manufacturing sectors, to effectively manage manual handling risks in consultation with employees (Heads of Workplace Safety Authorities 2007). During the campaign, WorkSafe Victoria developed a guide to safety in the metal fabrication industry (WorkSafe Victoria 2007c). This document was used by a number of jurisdictions whose targeted manufacturing sector was sheet/structural fabricated metal manufacturing. As part of the project, a total of 334 workplaces were audited. Overall, the outcomes of the compliance audits indicated high levels of workplace manual handling compliance (workplaces performed a risk management process), which contrasted with the high injury rates of manual handling injuries within the manufacturing sector. One possible explanation for this discrepancy may be the nature in which risk management is expected to be triggered by workplaces. Tasks that are thought to be hazardous (i.e., present with risk factors) are expected to be identified, assessed, and managed. Unfortunately, many manual tasks performed by workers in this industry do not appear to be hazardous when looked at individually; however, the cumulative nature of exposing workers to multiple tasks that have several low-level risk factors poses more of a risk (e.g., grinding tasks that expose workers to sustained awkward postures, repetitive movement, and hand-arm vibration as shown in Figure 44.1). Some of the key drivers for effective management of manual handling risks were management commitment, positive safety culture, increases in productivity, and reduced workers compensation costs. Barriers included lack of management commitment, lack of awareness of OHS obligations, poor workplace culture, and costs of replacing or upgrading equipment.

44.3.6 Jurisdictional Activity The numbers of scientific officers specializing in ergonomics that are employed by authority bodies across Australia vary greatly, and the roles of these specialists have changed over time. As an example, scientific officers of the human factors and ergonomics team at WorkSafe Western Australia (WA) have experience and educational background in an ergonomics-related discipline and are trained to be inspectors with legal powers to enforce the OSH laws where required. All inspectors at WorkSafe WA are expected to use a balance

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FIGURE 44.1  Metal manufacturing worker performing a deburring task using a hand-held grinder.

of education and enforcement for the purpose of improving health and safety in the state. The role of the scientific officers/inspectors in WA includes conducting national and statewide proactive projects (targeted investigations of high-risk industries and specific hazard types); conducting reactive investigations (investigations of reportable injuries and highrisk incidents and public enquiries); contributing to the development of ergonomics-related publications, legislation, and policy; providing educational sessions at public forums and workshops; assisting in investigations and providing skills development courses for industry team inspectors; and conducting complex investigations of human factors and ergonomics-related hazards. Hazard types that the team has focused on over the past few years include those related to MSDs, slips, trips, and falls, and psychosocial and organizational issues especially associated with work-related stress, conflict in the workplace, aggression, and violence. Most publications that are produced by jurisdictional authority bodies across Australia that have ergonomics-related principles have been written in plain English, with little technical jargon. Concepts have been simplified so that these publications may serve as practical guidance without the need for ergonomics specialist to interpret them. Some useful publications written by various jurisdictions include the codes of practice for manual handling and manual tasks (WorkCover Corporation of South Australia 1990; Commission of Occupational Safety and Health of Western Australia 2000; Victorian WorkCover Authority 2000; Workplace Health and Safety Queensland 2000); industryspecific manual task guidance material for the metal fabrication, saw milling, transport, textile, food and meat processing, mining, and council workers (Department of Health Safety and Welfare of Western Australia 1991, 1992; WorkSafe Victoria 2001, 2002, 2005, 2006a, 2007c; Department of Mines and Petroleum 2009); patient handling (Department of Health Safety and Welfare of Western Australia 1989; WorkSafe Victoria 2007b, 2009);

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office ergonomics(WorkSafe Victoria 2006c); slips, trips and falls (Commission of Occupational Safety and Health of Western Australia 2004; WorkCover New South Wales 2006; WorkSafe Victoria 2006b; Workplace Health and Safety Queensland 2007); work-related stress (WorkSafe Victoria 2007a; Workplace Health and Safety Queensland 2009); and aggression and violence in the workplace (NSW Health 2003; WorkSafe Victoria 2008).

44.4 ERGONOMICS RESEARCH Welford wrote in 1976 that with a population of only 13 million, Australia spends a far smaller proportion of its national income on research and development compared to other advanced countries, and that many of the best university students from that time have stayed overseas after leaving to gain wider research experience (Welford 1976). Although funding designated for human factors and ergonomics research in Australia remains limited, the proliferation of publications in the field of ergonomics since the 1970s shows that several key researchers have been innovative in obtaining necessary funds to conduct quality research in this field. A number of university departments in Australia have been successful in attracting researchers and students from overseas, as well as retaining their students to create productive research teams. 44.4.1 Early Research Early ergonomics-related research focused on the aviation industry. Factors relating to visual standards, changes in atmospheric pressure with altitude, the problems of blackout in aircrew, and the problems of noise in aircraft were areas of particular interest (Bullock 2001). Dr. John Lane, Director of Aviation Medicine, published one of the early papers on ergonomics in 1953 entitled “Human Engineering: A new technology” (Lane 1953). A human engineering research group was established within the Aeronautical Research Laboratories of the Australian Defence Scientific Service in the Department of Supply, in about 1957. This represented the first formally constituted research group in ergonomics as such in Australia. Three of the principal researchers associated with this group, Dr. Colin Cameron, Prof. Ron Cumming, and Dr. John Lane, were to become instrumental in the later formation of the Ergonomics Society. The design of air traffic control systems, navigational aids to assist aircraft landing, and visual displays to eliminate irrelevant information and assist the operator to organize incoming data were also subjects of interest. Lane invited Dr. Margaret Bullock from the University of Queensland (UQ) to undertake functional anthropometric and force capabilities studies of relevance to design of small aircraft cockpits and standards for parachute rip cord release in the 1970s (Bullock 1973, 1974, 1978, 2001). Colin Cameron went on to study and write about the theory of fatigue (Cameron 1973) and how it presented in modern industry (Cameron 1971). The effects of climate provided a special research interest. The Tropical and Fatigue Laboratory within the Department of Physiology at the UQ led major studies into the physical and psychological effects of tropical service, and the design of clothing for flying in the tropics and at low temperatures. Other studies in the School of Public Health and Tropical Medicine at the University of Sydney investigated the effects of climatic extremes

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on comfort and performance of people of all ages, whether healthy or sick. Dr. Provins, in South Australia, was concerned with studying the relationship between environmental conditions, body temperature, and the performance of skilled tasks (Provins and Cunliffe 1972a; Cumming 1973; Provins et al. 1973). He published several articles in the area of motor skill and handedness in the 1960s and 1970s (Provins and Clarke 1960; Provins 1967; Provins et al. 1968; Provins and Glencross 1968; Provins and Cunliffe 1972a,b,c). The results of these studies had application to work at Australia’s station at Mawson, in Antarctica, and in the mining industry in Northern Australia. Engineers became actively involved in designing safety features in the design of load haul dump (LHD) vehicles and underground mining vehicles (Bullock 2001). Collaborative research studies by the Departments of Mechanical Engineering and Physiotherapy at the UQ investigated the skills demanded of LHD vehicle drivers in coping with vibration. In an attempt to control the prevalent back injuries in industry and agriculture, extensive studies were carried out by Professor Margaret Bullock to determine the optimal worker-pedal relationship to minimize spinal movements. The physical stresses associated with manual sugarcane harvesting led engineers to develop an automated system of cane harvesting and bulk storage (Bullock 2001). Demonstrating an early interest in rehabilitation ergonomics, engineers and medical practitioners collaborated in the 1960s to examine upper limb stresses in process work and the design of prosthesis which would enable disabled persons to become productive workers (Bullock 2001). Considerable research was also carried out during the 1970s and 1980s by Dr. Patkin (Patkin 1967, 1977, 1978, 1981), in the ergonomic design of surgical instruments, The development of ergonomics practice in Australia has been closely associated with interests in OHS. The excessive amount of lost time from work because of musculoskeletal injury and the subsequent costs forced employers to introduce measures of control. Positive changes in OHS practices and also in management style were introduced into many work places in Australia during the 1980s, due in part to the major contributions of David Ferguson (Ferguson 1969, 1972, 1973). In the early 1970s, the association between repetitive activity and posture and increased risk of musculoskeletal problems was established, especially in relation to process work and keyboard work (Ferguson 1971; Duncan and Ferguson 1974; Ferguson and Duncan 1974). In the 1980s, an influx of neck and upper limb disorders being reported as associated with keyboard work, termed RSI, was considered an “epidemic” in Australia (Oxenburgh et al. 1985; Hall and Morrow 1988; Quintner 1989; Ireland 1995, 1998; Gun and Jezukaitis 1999; Awerbuch 2004). Intense activity on the subject of “repetitive strain injury” coupled with new OSH legislation in Australia in the early 1980s led to an influx of ergonomics society members from the OH&S profession (Howie et al. 1988). Howie et al. describe that at that time, a simplistic biomechanical approach was taken, only to find after considerable moneys being spent on “ergonomic” furniture that problems were not solved. The authors also felt that although the reputation of ergonomics suffered as a result of this approach, it prompted the realization that a broader systems approach is necessary. The increasing use of computers as part of the new technology and the importance of developing effective user interfaces

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later led to the formation of a Computer-Human Interaction Special Interest Group of the ESA (Bullock 2001; Human Factors and Ergonomics Society of Australia 2009a). In the 1970s, Welford published extensively in the area of cognitive ergonomics, including the influence of perception, mental load, and stress on performance, particularly reaction time (Welford 1970, 1971, 1973, 1978). One of Welford’s early publications looked at the ergonomic approach to social behavior (Welford 1966). 44.4.2 Recent Research Ergonomics research in Australia since the 1980s has covered many areas of interests including MSDs; health-care ergonomics; mining; transport; agriculture; slips, trips, and falls; anthropometry; human–computer interaction HCI; product design; human motor skill; job demands; and cost-benefit analysis of ergonomics intervention. 44.4.2.1  Musculoskeletal Disorders MSDs have been a focal area of research in Australia since the 1980s. The risk factors of interest have included static and awkward postures, forceful exertion, repetitive movement, and psychosocial factors. These have been related to spinal pain, manual handling, computer interaction, prevalence in children, workplace assessments, and various psychosocial factors.

44.4.2.1.1  Spinal Pain  Biomechanical studies conducted at the School of Physiotherapy at Curtin University of Technology have explored various patterns of muscular activity and sitting postures associated with nonspecific lower back pain (Dankaerts et al. 2006b; O’Sullivan et al. 2006). One of the studies (Dankaerts et al. 2006a) explored whether there were differences in trunk muscle activation during usual unsupported sitting between healthy controls and two subgroups of nonspecific chronic low back pain (LBP) patients. The authors concluded that subclassifying nonspecific chronic LBP patients into active extension pattern and flexion pattern patients revealed clear differences in surface EMG activity during sitting between pain-free subjects and subgroups of nonspecific chronic LBP patients. The flexion relaxation ratio of the back muscles was lower for nonspecific chronic LBP, suggesting a lack of flexion relaxation for those with nonspecific chronic LBP. A number of reviews have been conducted on the prevalence and associated factors for thoracic pain in the working and general population (Briggs et al. 2009a,b; Briggs and Straker 2009). 44.4.2.1.2  Manual Handling  The risks associated with various manual techniques and patterns of movement used during manual handling tasks have been explored by various methods including biomechanical, psychosocial, psychophysical, and physiological methods. Many of these studies were conducted at Curtin University of Technology and UQ (Burgess-Limerick et al. 1995; Burgess-Limerick and Abernethy 1997a,b, 1998; Straker et al. 1997a,b; Straker and Cain 1999; Straker and Duncan 2000; Burgess-Limerick 2003). Straker’s ­studies in 1997 aimed to compare the risks assessed in single manual handling tasks with those in combination tasks (of pull, lift, carry, lower, and push), as most recommendations

1144    ◾    Occupational Ergonomics: Theory and Applications

assume that a combination task can be split into its components for assessment (Straker et al. 1997a,b). Their studies found that in at least one of the twelve comparisons performed for each dependent variable, the combination-task value was significantly different to each single-task value. The differences occurred regardless of whether the most critical single-task value or an average of all single-task values was used. The authors concluded in their first study that the risk in combination manual tasks cannot be accurately assessed by using estimates from discomfort, exertion ratings, and heart rate measures of single tasks. In their second study the maximum acceptable weight (MAW) of each combination task was compared to the MAWs of the single tasks. It was concluded that the current use of single-task MAWs to estimate the risk in combination tasks was unacceptable. Prediction models for combination-task MAWs based on single-task MAWs were also developed. It was argued that owing to their situation-specific nature, the prediction of combinationtask risk using single-task MAWs was likely to result in unacceptable risk errors. Burgess-Limerick’s studies defined the stoop and squat postures and how they interrelated. In one of his studies, he found that two distinct patterns of coordination were evident during a cyclic lift and lowering task: a squat technique in which moderate range of hip, knee, and ankle movement was utilized and ankle plantar flexion occurred simultaneously with knee and hip extension; and a stoop technique in which the range of knee movement was reduced and knee and hip extension was accompanied by simultaneous ankle dorsiflexion (BurgessLimerick et al. 2001). Abrupt transitions from stoop to squat techniques were observed during descending trials, and from squat to stoop during ascending trials. The authors of this study believed that the transitions may be a consequence of a trade-off between the biomechanical advantages of each technique and the influence of the lift height on this trade-off. The effectiveness of participatory ergonomics for the reduction of the risk and severity of injuries from performing manual handling and manual tasks has been evaluated by several researchers (Straker et al. 2004; Carrivick et al. 2005; Burgess-Limerick et al. 2007). Carrivick et al. (2005) evaluated the effectiveness of a participatory ergonomics risk assessment approach in reducing the rate and severity of injuries from manual and nonmanual handling sustained by a cohort of 137 cleaners within a hospital setting. The date of injury and the workers’ compensation claim cost and hours lost from work were obtained for each injury incurred during a 4 year preintervention and 3 year intervention period. Reductions of rate of injury by two-thirds, workers’ compensation claim costs by 62%, and hours lost by 35% for manual handling injuries were found to be associated with the intervention period. Straker et al. (2004) showed that participatory ergonomics can reduce the risks associated with performing manual tasks. The authors conducted a randomized controlled trial on 117 small to medium sized food, construction, and health companies, where participative ergonomics was the intervention. Workplaces were audited by government inspectors using a manual tasks risk assessment tool. The results showed a significant decrease in estimates of manual task risks and suggested better legal compliance in the experimental group. 44.4.2.1.3  Computer Interaction  The risk of MSDs from performing computer work on laptops and standard desktops have been explored extensively, especially in relation to

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actions and postures associated with mouse and keyboard design and interaction, and screen design and position (Straker et al. 1997a,b; Burgess-Limerick et al. 1998, 1999a,b, 2000; Cooper and Straker 1998; Mon-Williams et al. 1999; Burgess-Limerick and Green 2000; Cook et al. 2000, 2004a,b; Evans and Patterson 2000; Straker and Mekhora 2000; Lindgaard and Caple 2001; Szeto et al. 2002, 2005a,b,c,d; Cook and Burgess-Limerick 2004; Straker et  al. 2008, 2009b,e). Musculoskeletal discomfort among bank tellers and seated versus standing postures have also been studied (Roelefs and Straker 2002). After years of research in this area and continued evidence of the rapid adoption of information technology in the workplace, it has been argued that many modern workers are at risk of insufficient physical workload and ergonomics will require a change in paradigm to tackle this issue (Straker and Mathiassen 2009). It is argued that the traditional physical ergonomics paradigm of reducing risk by reducing physical loads (“less is better”) is not appropriate for many modern occupations. Straker and Mathiassen recently proposed that a new paradigm is required, where “more can be better.” Their paper discusses the potential for work to be seen as an arena for improving physical health and capability and the challenges and responsibilities presented by this new paradigm for ergonomists, employers, health, and safety authorities and the community. 44.4.2.1.4  Prevalence in Children  The published research on the current and potential deleterious effect and impact of information technology on children and adolescents continues to grow especially in relation to MSDs, postural changes, and muscular activity (Harris and Straker 2000; Zandvliet and Straker 2001; Straker et al. 2002, 2006, 2007, 2008a,b,c,d, 2009a,c; Briggs et al. 2004; Greig et al. 2005). The collective studies of Straker and Pollock in the field of information technology and children have prompted the publication of a review of current exposure data and the evidence for positive and negative effects of computer use by children (Straker et al. 2009d). The authors described that the potential positive effects of computer use by children include enhanced cognitive development and school achievement, reduced barriers to social interaction, enhanced fine motor skills and visual processing, and effective rehabilitation. However, the negative effects are beyond physical issues related to MSDs and include threats to child safety, inappropriate content, and exposure to violence, bullying, Internet “addiction,” displacement of moderate/vigorous physical activity, exposure to junk food advertising, sleep displacement, and vision problems. Progress toward childspecific guidelines is reported in their paper, with a set of guideline principles presented as the basis for more detailed guidelines on the physical, cognitive, and social impact of computer use by children. Ranelli et al. (2008) explored the development of MSDs in musicians during childhood. This study investigated the risk factors and established the prevalence of playing-related musculoskeletal problems and their association with gender and age. This study found that females and older children were more likely to experience both symptoms and disorders. For children having reported the experience of a playing-related musculoskeletal symptom within the last month, 5% took medication to relieve the problem and 4% visited a health professional to seek advice for the problem.

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44.4.2.1.5  Workplace Assessments  Work-related assessments such as functional capacity evaluation and workplace assessments have been analyzed and written about in ­several publications by various authors especially Innes and Straker (Innes and Straker 1998a,b,c, 1999a,b, 2002a,b, 2003a,b; Tuckwell et al. 2002; Legge and Burgess-Limerick 2007). Innes and Straker conducted two studies to determine the extent and quality of available evidence for the validity and reliability of work-related assessments. The study examined available literature and sources in order to review the extent to which validity and reliability have been established for 28 work-related assessments. Most work-related assessments were found to have limited evidence of validity and reliability. Of those that had adequate evidence of validity, the validity ranged from poor to good. There was no instrument that demonstrated moderate to good validity in all areas. Very few work-related assessments were able to demonstrate adequate validity in more than one area. For the limited number of work-related assessments with an adequate level of evidence on which to judge their reliability, most demonstrated a moderate to good level. Few assessments, however, demonstrated levels of reliability sufficient for clinical (and legal) purposes (Innes and Straker 1999a,b). Innes and Straker researched further on this subject to understand the current beliefs of therapists in Australia and the strategies they use to address the issues of credibility, reliability, consistency, trustworthiness, validity, generalizability, and quality in conducting work-related assessments. The authors found that participants were aware of the issues of reliability and validity but believed it was not practical to establish these aspects formally in most work-related assessments (Innes and Straker 2003a). 44.4.2.1.6  Psychosocial Factors  Significant reviews have been conducted looking at the association between psychosocial factors, workload, and stress on MSDs (Macdonald and Munk 2003; Macdonald 2004). Wendy Macdonald and Owen Evans conducted a review of literature on the prevention of work-related musculoskeletal disorders (WMSDs) for Safe Work Australia (Safe Work Australia 2006a). Their paper showed that cumulative WMSDs can stem from a wide range of factors that together result in an inadequate margin between people’s work demands and the coping resources available to them. They described the hazard as having both physical and psychosocial risk factors. The psychosocial risk factors included excessive amounts of work, long shifts, inadequate rest breaks, long weeks, time pressures, high responsibilities, inadequate time to cope with perceptual/cognitive task demands and excessive emotional demands of the work, inadequate personal control and autonomy, inadequate task variety and opportunities for skill utilization, and inadequate job security. They explained that besides exposure to certain risk factors, inadequate workplace support: poor materials/ information, poor supervisor support, poor social cohesion, low morale, and inadequate training provisions added to the risk. The factors mentioned earlier, whether singly or in combination, can result in hazardous personal states such as high levels of fatigue (of varying types) and/or of psychological stress, which entail physiological responses that directly increase injury risk; these states

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can also induce behavioral changes which increase risk. In addition, hazardous task and job demands, particularly their physical components, can directly increase the risk of acute-onset WMSDs. There is also some evidence that at least some physical and psychosocial hazards can act synergistically in increasing WMSD risk, but such interactions are inadequately understood and there is a need for more research on this topic. It is concluded that it is no longer appropriate for psychosocial hazards to be seen as necessarily secondary or peripheral to physical hazards for WMSDs, particularly in light of the accumulating evidence of physiological mechanisms via which elements of the “stress response” can directly increase the risk of WMSDs. In many documented situations, WMSD risk has been shown to be highest when both physical and psychosocial hazard levels are high. 44.4.2.2  Health-Care Ergonomics Patient handling and MSDs have been explored in various ways including the use of slings to handle people (Elford et al. 2000) and the implementation of no-lift policies as a highlevel control (Engkvist 2006, 2007). The prevalence and impact of MSDs in relation to the nursing, occupational therapy, and physiotherapy professions have also been studied in Australia (Cromie et al. 2000, 2002, 2003; Retsas and Pinikahana 2000; King et al. 2001; Martin 2003). The application of ergonomics in surgery has been studied and described in the areas of engineering technology. The studies are related to the use of robotics (Murphy et al. 2008), visual information, fine motor control, postures adopted, and instrument design (Patkin 1967, 1977, 1978, 1981; Patkin and Isabel 1995). The ergonomics and human factors of visual and auditory patient monitoring display systems especially in the field of anesthesiology have been explored extensively by Penny Sanderson and her research team members (Watson et al. 2000, 2004; Seagull and Sanderson 2001; Sanderson et al. 2003, 2004, 2005a,b, 2006, 2008, 2009; Watson and Sanderson 2004, 2007; Sanderson 2006; Lacherez et al. 2007; Thompson and Sanderson 2008; Wee and Sanderson 2008; Anderson and Sanderson 2009; Grundgeiger and Sanderson 2009; Liu et al. 2009a,b,c). Sanderson et al. (2009) outlined and discussed the work on auditory displays, covering both auditory alarms that indicate technical or physiological threshold levels and informative auditory displays that provide a continuous awareness of a patient’s well-being. The authors explained that auditory display in anesthesia can extend well beyond auditory alarms to displays that give the anesthesiologist a continuous peripheral awareness of patient well-being. However, they argue that much more rigorous approaches should be taken to evaluating auditory displays so they add information rather than noise. 44.4.2.3  Mining A few studies have been conducted in the mining industry, including injury trends (Burgess-Limerick and Steiner 2006) and ergonomic intervention in underground coal mining industry of which some have been funded by the Australian Coal Association Research Program (Burgess-Limerick 2005; Burgess-Limerick et al. 2007; Zupanc et al. 2007). Burgess-Limerick has also been involved in publications on the application and value of ergonomics in U.S. mining industries (Burgess-Limerick and Steiner 2007;

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Torma-Krajewski et al. 2007). Participatory ergonomics has been applied for the purpose of preventing MSDs, showing positive results (Burgess-Limerick et al. 2007). McPhee has published a review, a handbook on ergonomics, and a handbook on wholebody vibration exposure specifically for the mining industry (McPhee 1993, 2004; Mcphee et al. 2001). McPhee reported that risks to health and safety in the mining industry posed by longer shift lengths, higher workloads, less task variation, and decision latitude have not really been well researched. Heavy physical workloads and stresses are still areas of concern, but are likely to be intermittent rather than constant. A report commissioned by the NSW minister for mineral resources confirmed that working hours were high and fatigue was experienced by a significant number of workers interviewed in the industry (Shaw Idea 2007). This study has been reported as Case Study 3. McPhee points out that the contribution of slips, trips, and falls and increasing age of miners to manual handling injuries is still not clear. In some cases sedentary work and the operation of machinery have completely replaced heavy physical work. The issues of machinery design for operations and maintenance and whole-body vibration exposures when operating machines and vehicles are becoming more critical. The link between prolonged sitting, poor cab design, and vibration with back and neck pain is being recognized but has yet to be addressed in any systematic way by the mining industry (McPhee 2004). 44.4.2.4  Transport Monash University Accident Research Centre (MUARC), formed in 1987, is Australia’s largest multidisciplinary research center specializing in the study of injury prevention. The center undertakes applied research contracts for government and industry clients throughout Australia and internationally. More fundamental research is undertaken through research grants. A number of studies have centered around human factors including factors that may affect situational awareness (Salmon et al. 2009), human factors analysis from aviation crash (Lenné and Ashby 2008; Lenné et al. 2008a), railway crossings (Wigglesworth 2008), predicting pilot error (Stanton et al. 2009), the application of intelligent transport systems (Horberry et al. 2006b, 2007; Regan et al. 2007a,b; Salmon et al. 2007; Young and Regan 2007), driver distractions (Horberry et al. 2006a), including the use of mobile phones and text messaging (Hosking et al. 2006; Regan 2006), and detection of emergency vehicles (Lenné et al. 2008b). The MUARC has explored human error and road transport systems, developing a framework for an error-tolerant road (Salmon et al. 2006). The ergonomics unit of WorkSafe Australia was engaged to identify and assess ergonomic problems in driver cabs of older trains on the Sydney city and suburban network (Stevenson et al. 2000). Modeling and predicting workload in en route traffic control (Loft et al. 2007) and training systems in the field of aviation has also been explored (Naikar and Sanderson 1999). Besides the research conducted at MUARC, road safety research has also been conducted extensively at the University of New South Wales. Fisher and Hall conducted many studies on night driving, road lighting, and car frontal design on pedestrian accident trauma in the 1970s and 1980s (Fisher and Hall 1972, 1973, 1976, 1978, 1982, 1985a,b, 1986; Hall and Fisher 1972, 1978, 1980; Hall 1976, 1979, 1980).

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44.4.2.5  Agriculture Several studies have been conducted in the agriculture sector. A case-control study conducted in Victoria to identify risk factors for serious farm-work-related injury among men showed that the most common external causes of injury were machinery (26%), falls (19%), transport (18%), animals (17%), and being struck by an object (11%). Increased injury risk was observed for being an employee/contractor, not having attended farm training courses, absence of roll-over protective structures on all/almost all tractors, absence of personal protective equipment for chemical use, and a low average annual farm income (Day et al. 2009). The prevalence of headache and neck pain in farmers was explored in 1997 (Scutter et al. 1997). It was shown that 77.7% of farmers experienced neck pain and 79.2% experienced headaches. Driving a tractor was the activity which was most frequently described as increasing symptoms in both conditions. The contribution of factors related to driving a tractor, including being exposed to whole-body vibration and assuming a rotated neck posture, to the development of headache and neck pain were discussed by the authors. Although most of the recent research related to sheep shearing has been published in New Zealand, some studies have been conducted in Australia. One of these studies includes the analysis of the forces required to drag sheep over various surfaces (Harvey et al. 2002). Results of this study showed that significant changes in mean dragging force occurred with changes in both surface texture and slope. The best floor tested was a floor sloped at 1:10 constructed of timber battens oriented parallel to the path of the drag. Shearing in hot weather has been studied at the University of Adelaide (Gun RT and Budd GM 1995). Forty-three men were studied throughout 54 man-days of shearing sheep and pressing wool bales, in air temperatures 19°C–41°C and wet-bulb globe temperature index (WBGT) 16°C–29°C. Over the 10 h work day, the subjects sweated substantially, but they replaced their sweat losses so successfully that warmer weather and heavier sweating were not accompanied by significantly greater dehydration. It was shown that men with greater fat percentage felt cooler, and those who had drunk more alcohol the previous evening had lower core temperature readings and tended to be more productive. Age was not associated with any measured response. The findings highlighted the challenges in attempts to define safe limits for occupational heat stress, and they demonstrate the effectiveness of the behavioral responses that permit shearers to perform sustained strenuous work in a hot environment without excessive physiological strain. The Accident Research Centre at Monash University researched on the implementation of published guidelines for retrofitting tractors with safe access platforms, which were developed to reduce the risk of serious injuries and deaths associated with mounting and dismounting (Day and Rechnitzer 2004). The results were based on farmer interviews and engineering-based inspections. It was shown that platform retrofitting had little effect on tractor operations and substantially improved ease of access. The authors recommended that mechanisms to increase adherence to the key criteria of bottom step positioning and rear wheel guarding should be included in future promotion. Many of the recent publications on farmer’s health in Australia have focused on mental health problems, mental illness, and suicide (Judd et al. 2006; McShane and Quirk 2009; Fraser et al. 2005; Stain et al. 2008).

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Fraser et al. (2005) provided an overview of the literature examining mental health issues experienced by farming populations in the United Kingdom, Europe, Australia, Canada, and the United States and identifies areas for further research. This body of research studied male farmers, female farmers, farm workers, farming families, and young people living on farms. Research to date indicates that farmers, farm workers, and their respective families face an array of stressors related to the physical environment, structure of farming families, and the economic difficulties and uncertainties associated with farming which may be detrimental to their mental health. The authors concluded that while suicide rates in some groups of farmers are higher than the general population, conclusive data do not exist to indicate whether farmers and farming families experience higher rates of mental health problems compared with the nonfarming community. It is clear, however, that farming is associated with a unique set of characteristics that is potentially hazardous to mental health and requires further research. 44.4.2.6  Slips, Trips, and Falls There have been few studies conducted on occupational slips, trips, and falls in Australia. Many fall-related studies and peak body initiatives in Australia have been conducted for community-wide purposes, especially in relation to aged care (State Government Victoria 2007; Injury Control Council or Western Australia 2009; Mackenzie 2009; Comans et al. 2009; Hill et al. 2009; Mackenzie et al. 2009). Having said that, a recent epidemiological study conducted by MUARC and commissioned by the Australian Building Codes Board (ABCB) was successful in placing research findings into the context of policy (Ozanne-Smith et al. 2008). Slip, trip, and fall injuries were examined across three levels of severity: emergency department presentations (without admission), hospital admissions, and deaths. Through a preliminary analysis of state, national, and international data and as identified in similar studies conducted internationally, the most prevalent hazards and harms related to slips, trips, and falls and the design and construction of buildings were identified. The major building structural and design components identified as being associated with fall injuries in this study were flooring surfaces, stairs, windows, balconies, verandas, and, indirectly, guttering and roofs in residential settings. Epidemiological data in this study show that many of the victims of fall injuries in buildings are from vulnerable populations, particularly the elderly, the sick, and children. The authors argued that these community members are equally entitled to a safe environment as the more physically robust members of society. Accordingly they should be protected by the Building Code of Australia and innovation in safe building design and construction. Other studies related to occupational falls include issues related to wearing of fall-arrest harnesses in the construction (Zupanc and Burgess-Limerick 2003), horse-racing falls (Hitchens et al. 2009), portable ladder use (Shepherd et al. 2006), and injury trends of farmers (Day et al. 2009), miners (McPhee 2004), occupational spinal cord injuries (O’Connor 2001), and injuries from unpaid work at home (Driscoll et al. 2003).

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44.4.2.7  Anthropometry It has been shown that updated anthropometric data to be used for the Australian workforce has been lacking for some time. A report commissioned by the ASCC (Safe Work Australia 2009) showed that some anthropometric data targeted at working populations in Australia are proprietary or commercial-in-confidence. Of the publicly available data, many are out of date or of military origin, not civilian population-based, and thus, they are of limited value when applied to civilian populations. Some Australian standards contain anthropometric data, but this is out of date and therefore unreliable. There are international data available but they are not necessarily relevant to the Australian population. Designers, advisers to designers, and evaluators of products and spaces consulted during this project expressed their needs now, and into the future, for reliable, high-quality, accessible, and affordable anthropometric data that can inform their work. However, there is optimism in the future as the researches acknowledged that recent formation and rapid growth of HFESA’s Anthropometry Resources Australia Special Interest Group (ARASIG) provides a forum for users and producers of anthropometric data in Australia that could be used to educate and inform people. A further emerging source of anthropometric data is the international, not-for-profit group, World Engineering Anthropometry Resource (WEAR). The database will contain some Australian data, and there is potential to produce further data and lodge it with WEAR for international use. Further to the earlier findings, there has been recent activity in the gathering of anthropometrics data across Australia. The Australian Defense Anthropometric Personnel Testing project is a collaborative project of a number of high-profile national and interstate organizations, including the Australian Government Department of Defence, University of South Australia, Australian Government Australian Sports Commission, Sinclair Knight Merz (SKM), and University of Ballarat. These partners have joined together to undertake a project using Vitus Smart 3D whole-body scanner to gather and assess information about the size of potential aircrew recruits and their fit in the current inventory of ADF aircraft. The immediate aim of the project is to determine the appropriate body size and shape for aircrew flying a variety of aircraft. The longer-term aim is to develop a capability in a variety of new technologies for measuring human body size and shape and simulating the movements of aircrew in aircraft. Data was collected in 2009 from major cities of Australia, including Adelaide, Melbourne, Canberra, Brisbane, Sydney, and Perth. Most candidates were men and women aged 18–30, particularly those people who have technical or university qualifications, or who are currently enrolled courses (UniSA 2009). Prior to the works described earlier, the development of normative data for hand strength and anthropometric dimensions in a population of automotive workers was conducted and published in 2007 (Kunelius et al. 2007). 44.4.2.8  Human–Computer Interaction HCI research is conducted at various pockets of the country, especially at the UQ and Monash University. Sanderson’s group at UQ have explored HCI models, theories, and frameworks and have applied them to various industries including defence and

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hydropower systems (Naikar and Sanderson 2001; Naikar et al. 2003; Sanderson 2003; Li et al. 2006). Monash University has conducted extensive amounts of research on cursor control devices(Phillips and Triggs 2000, 2001; Phillips et al. 2001, 2003a,b; Stevenson et al. 2004; Memisevic et al. 2007). 44.4.2.9  Product Design Roger Hall, at the University of New South Wales, has written extensively on the ergonomics of product design and the prototyping (Hall 1998, 2001), and explored the usability of time functions on small electronic consumer products(Hall et al. 1998). 44.4.2.10  Human Motor Skill Provins published newer studies in the area of manual asymmetry and motor skill in the 1990s (Provins and Magliaro 1993; Provins 1997). His publications show and discuss the activity-specific nature of motor skills. The findings of his studies show the importance of using the same criteria in making preference for performance comparisons and highlight the need to recognize and control the influence of previous training or experience. Welford concentrated on cognitive ergonomics in the 1970s, but his more recent work focuses on the effects of ageing on work performance (Welford 1988a,b). 44.4.2.11  Job Demands The ergonomics research team at Latrobe University, including Macdonald and Peterson, have contributed in the area of workload, job demands, job satisfaction, fatigue, stress, performance, health, and well-being (Peterson 1994; Macdonald and Bendak 2000; Weeks et al. 2000; Murphy et al. 2002; Macdonald 2003, 2006a,b; Peterson 2003). 44.4.2.12  Cost-Benefit Analysis Oxenburgh has worked on and written about the concept of cost-benefit analysis and developed models in relation to ergonomics and other health and safety intervention (Oxenburgh and Guldberg 1993; Oxenburgh and Marlow 2005; Oxenburgh 2004) which have been applied independently in the health-care industry (Busse and Bridger 1997).

44.5 APPLIED ERGONOMICS AND CASE STUDIES Ergonomics has been applied in most industry sectors in Australia. However, the evidence of implementation and uptake has been more apparent in some industries compared to others. For example, the health-care industry have applied widespread changes as No or Minimal Lift Policy programs were implemented across the nation, especially the state of Victoria, where the nursing board, in collaboration with other peak bodies, drove this intervention (State Government Victoria 2002). On the contrary, the construction industry, especially trade services, appears to have few publicized ergonomics intervention programs. WorkSafe WA produced a series of publications on reducing the risk of manual handling injuries in various trade services, including bricklayers, form workers, block layers and stonemasons, electricians, plasterers, and roof carpenters (WorkSafe WA 2009). These were formulated following stakeholder meetings with

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employer and employee representation. However, there have been no studies conducted to measure the level of uptake of the information. Three case studies have been presented in the following. The first two cases are of specific interventions that were implemented in two companies that were working toward reducing the risk of MSDs in the workplace. The third case study is of a wider-scoped project that aimed to assess the impact of remuneration methods, fatigue management, and OHS management systems on OHS performance in the mining industry. Case Study 1 An assay lab that conducts chemical analysis of soil samples had a job role that required the workers to grind soil samples to be analyzed using a semiautomated grinding machine. The job required a worker to retrieve soil samples from a trolley placed next to their workstation, place soil samples in the grinding machine, close the grinder door, switch the grinder on, place ground soil samples into labeled bags, and clean the grinder before the next process is conducted (as shown in Figure 44.2). Issues that presented were shoulder and wrist discomfort and exposure to dust (which have unknown levels of hazardous substances). The task required continuous hand and arm activities, exposing that part of the body to high biomechanical forces when lifting the metal rings of the machine and repetitive movement when bagging the soil samples. The company looked at various controls to tackle the source of the problem, which stemmed primarily from the design of the grinder machine and process. After evaluating what was available on the market and conducting a cost analysis, the executives decided to completely eliminate the semiautomated grinding process by using robotic technology. The supplier of the robotic machine tailored a design specifically for the company. The company has

FIGURE 44.2  Semiautomated grinding workstation: worker lifting metal rings before vacuuming

the dust off the grinder.

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FIGURE 44.3  Robotic system performing the grinding task equivalent of six semiautomated

grinding machines.

since found that the robotic arm can perform the task of six semiautomated grinders at a faster pace than before (as shown in Figure 44.3). Case Study 2 The next case study is of the simple interventions that have taken place in a metal manufacturing company that produces small metal parts, primarily for the construction industry. Many of the workers in this organization have physical and cognitive limitations. Processes, systems of work, work-area layout, workstations, and equipment throughout the workplace have been selected and designed for individual workers. To achieve health, safety, and productivity targets, collaboration and continuous consultation take place between the operations managers, engineers, occupational therapists, and workers within the organization. Two examples of cost-effective ergonomics interventions include the following: 1. The design of a workstation for an individual with physical and cognitive limitations for a cardboard box assembling task. A bracket which helps form and stabilize the cardboard boxes while it is stapled together was developed, and a footrest was designed to suit the worker, to couple with the adjustable chair he was supplied with (as shown in Figure 44.4). 2. The intervention is of the design of a trolley tailored for the movement of metal sheeting. These were not commercially available and therefore were created in-house using suitable castors and brackets for metal sheets to be wheeled rather than manually lifted around the factory (as shown in Figure 44.5).

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FIGURE 44.4  Metal manufacturing worker assembling boxes using a specially designed bracket

and footrest.

FIGURE 44.5  Specially designed trolley for transporting metal sheets.

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Case Study 3 Digging Deeper (Shaw Idea 2007) was a research project conducted in the mining industry and commissioned by the NSW minister for mineral resources aimed to assess the impact on OHS performance of • Production bonus payments and safety-based incentive schemes • Fatigue management and working hours in the mining industry • OHS management systems and consultation The researchers found that production bonus and safety incentive schemes that involve payment in exchange for achieving particular safety outcome targets have not proved themselves to consistently or reliably improve safety outcomes. Generally, sites reported that safety incentive schemes making payments as a result of achievement of outcome targets either made no difference at all or had negative effects on incident reporting. It was evident that hours of work in the NSW mining industry are high (average 49.8 per week) and far in excess of the hours worked in the mining industry on average around Australia (average 44.7 per week). The factors found to affect the hours worked were occupation (with management and professionals working longer hours), subsector, employment status (with contractors working longer hours), size of company (with large company workers working longer hours), and location. Many people interviewed reported that they were fatigued as a result of their hours of work and shift arrangements. Respondents reported statistically significant differences between fatigue according to shift. Night shift was reported to cause significantly worse effects on work performance and fatigue levels than either afternoon or day shift. The researchers found limited evidence that sites had a thorough understanding of the causes of fatigue, with most attitudes to fatigue focused around nonwork causes, rather than the contributions made by working arrangements. It was found that the importance of addressing the interrelated personal and organizational factors was not widely recognized. While the researchers found excellent examples of engineering risk controls, they also saw some reluctance on the part of the industry to manage risks at source. This was coupled with an increasing take-up of strategies that focus on worker behavior as the primary means of risk control. Twenty-five recommendations were provided to the NSW Department of Primary Industries, based on the findings of this project.

44.6 ERGONOMICS TRAINING PROGRAMS Initially, education in ergonomics in Australia use to be offered within relevant professional programs, including engineering, psychology, physiology, architectural science, physiotherapy, occupational health, and applied arts and industrial engineering. Today, postgraduate qualifications in ergonomics (at postgraduate diploma or masters degree level) are offered within several tertiary institutions. No undergraduate program totally devoted to the preparation of an ergonomist is offered within Australia. In 2009, two universities were found to offer these courses including

Overview of Ergonomics in Australia    ◾    1157  

1. The UQ—graduate certificate in ergonomics, diploma in ergonomics and masters of ergonomics (University of Queensland 2009) 2. LaTrobe—graduate certificate in occupational health, safety and ergonomics and masters of ergonomics, safety and health (La Trobe University 2009) The IEA guidelines for accreditation of ergonomics education programs developed by an IEA committee chaired by Professor Margaret Bullock were accepted by the society, and these have also provided a resource for outlining curricula and philosophies for new ergonomics educational programs in Australia (Bullock 2001).

44.7 EMERGING ISSUES The emerging issues apparent in Australia are very similar to those of other developed countries including greater use of computers by children and adults (Straker et al. 2006, 2007), increased sedentary work (Straker and Mathiassen 2009), increased social isolation at work, greater mobility of workers between jobs in a market-driven economy (Caple 2008), increased reports of work-related mental health disorders (Safe Work Australia 2006c), an ageing workforce (Safe Work Australia 2005), increased levels of obesity in the community, and changing anthropometrics (Safe Work Australia 2009b,c).

44.8 STUDY QUESTIONS 1. Are there any regulations in Australia that relate to the prevention of MSDs? If so, what are they called and in which states do they exist? Answer:

a. Yes there are regulations that target MSDs.



b. They are commonly termed “manual handling” or “manual task” regulations.



c. They exist in all jurisdictions, including Australian Capital Territory, Northern Territory, Western Australia, Queensland, Victoria, South Australia, New South Wales, and Tasmania.

2. List 3 emerging issues in Australia and discuss them briefly, including whether they may be unique to Australia or be common in other developed countries, and how they may have an impact on future ergonomics work in the Australia. Answer:

a. Emerging issues: • Use of computers by children and adults • Increased sedentary work

1158    ◾    Occupational Ergonomics: Theory and Applications

• Increased social isolation at work • Greater mobility of workers between jobs in a market-driven economy • Increased reports of work-related mental health disorders • An ageing workforce • Increased levels of obesity in the community • Changing anthropometrics

ACKNOWLEDGMENTS Kathryn Jones, Rodney Powell, Christina Paterson, Rosalind Forward, and John Innes at WorkSafe WA for assistance and support. David Caple, Robin Burgess-Limerick, and Leon Straker for names of leading researchers and topics of interest. Margaret Bullock for her most recent contribution on the history of ergonomics in Australia to the society. Effie Mangharam and Henri Rose for technical edits, encouragement, and support.

REFERENCES Anderson, J.E. and P. Sanderson, Sonification design for complex work domains: Dimensions and distractors, J Exp Psychol: Appl, 15(3): 183–198 (2009). Australia, S., Sizing up Australia: How contemporary is the anthropometric data Australian designers use? South Australia, Canberra, Australian Capital Territory, Australia, Commonwealth of Australia, 2009. Australian Bureau of Statistics, Population projections Australia 2006 to 2101, Canberra, Australian Capital Territory, Australia, Commonwealth of Australia, 3222.0, 2008. Australian Bureau of Statistics, Australian demographic statistics march quarter 2009, Canberra, Australian Capital Territory, Australia, Commonwealth of Australia, 3101.0, 2009. Australian Bureau of Statistics, Labour force Australia October 2009, Canberra, Australian Capital Territory, Australia, Commonwealth of Australia, 6202.0, 2009. Australian Bureau of Statistics, Year Book Australia, 2009–2010, Canberra, Australian Capital Territory, Australia, Commonwealth of Australia, 1301.0, 2010. Australian Safety and Compensation Council, Guidance on the principle of safe design for work, Canberra, Australian Capital Territory, Australia, Commonwealth of Australia, 2006. Australian Safety and Compensation Council, National code of practice for the prevention of musculoskeletal disorders from performing manual tasks at work, Canberra, Australian Capital Territory, Australia, Commonwealth of Australia, 2007a. Australian Safety and Compensation Council, National standard for manual tasks, Australian Government, Canberra, Australian Capital Territory, Australia, Commonwealth of Australia, 2007b. Australian Safety and Compensation Council, Overweight and obesity: Implications for workplace health and safety and workers’ compensation, Australian Safety and Compensation Council, Canberra, Australian Capital Territory, Australia, Commonwealth of Australia, 2008. Australian Safety and Compensation Council, National hazard exposure worker surveillance (NHEWS) survey: 2008 results, Canberra, Australian Capital Territory, Australia, Commonwealth of Australia, 2009.

Overview of Ergonomics in Australia    ◾    1159   Awerbuch, M., Repetitive strain injuries: Has the Australian epidemic burnt out? Intern Med J, July; 34(7): 416–419 (2004). Briggs, A.M. and P. Bragge et al., Prevalence and associated factors for thoracic spine pain in the adult working population, a literature review, J Occup Health Saf Aust NZ, 51(3): 177–192 (2009a). Briggs, A.M. and A.J. Smith et al., Thoracic spine pain in the general population: A systematic review of prevalence, incidence and associated factors in children, adolescents and adults, BMC Musculoskelet Disord, 10: 77 (2009b). Briggs, A. and L. Straker et al., Upper quadrant postural changes of school children in response to interaction with different information technologies, Ergonomics, 47(7): 790–819 (2004). Briggs, A.M. and L.M. Straker, Thoracic spine pain in youth: Should we be concerned, Spine J, 94(4): 338–339 (2009). Browne, R.C., Safety and health at work: The Robens report, Br J Ind Med, 30: 87–91 (1973). Bryan Bottomley and Associates, Identification of compliance requirements and tools for an effective risk management process for the national standard and code of practice for manual handling, National Occupational Health and Safety Commission, Canberra, Australian Capital Territory, Australia, Commonwealth of Australia, 2003a. Bryan Bottomley and Associates, An assessment of current performance indicators as a measurement tool and the development of an adaptive model best practice for physical handling in the work environment, National Occupational Health and Safety Commission, Canberra, Australian Capital Territory, Australia, Commonwealth of Australia, February 2003b. Bullock, M.I., Cockpit design—Pilot accommodation and accessibility to controls, Aerosp Med, November; 44(11): 1295–1299 (1973). Bullock, M.I., The determination of functional arm reach boundaries for operation of manual controls, Ergonomics, May; 17(3): 375–388 (1974). Bullock, M.I., Ripcord release capability of female parachutists, Aviat Space Environ Med, October; 49(10): 1177–1183 (1978). Bullock, M.I., Australia: Ergonomics society of Australia, International Encyclopedia of Ergonomics and Human Factors, W. Karwowski (ed.), Vol. 1, Taylor & Francis, London, U.K., and New York, 2001. Burgess-Limerick, R., Stoop, squat, or something in-between, Int J Ind Ergon, 31: 143–148 (2003). Burgess-Limerick, R., Reducing injury risks associated with underground coal mining equipment, Ergono Aust, 19(2): 14–20 (2005). Burgess-Limerick, R. and B. Abernethy et al., Self-selected manual lifting technique: Functional consequences of interjoint coordination, Hum Factors, 37: 395–411 (1995). Burgess-Limerick, R. and B. Abernethy, Towards a quantitative definition of manual lifting postures, Hum Factors, 39: 141–148 (1997a). Burgess-Limerick, R. and B. Abernethy, Qualitatively different modes of manual lifting, Int J Ind Ergon, 19: 413–417 (1997b). Burgess-Limerick, R. and B. Abernethy, Effect of load distance on self-selected manual lifting technique, Int J Ind Ergon, 22: 367–372 (1998). Burgess-Limerick, R. and W. Green, Using multiple case studies in ergonomics: An example of pointing device use, Int J Ind Ergon, 26: 381–388 (2000). Burgess-Limerick, R. and M. Mon-Williams et al., Visual display height, Hum Factors, 42: 140–150 (2000). Burgess-Limerick, R. and A. Plooy et al., The effect of imposed and self-selected computer monitor height on posture and gaze angle, Clin Biomech, 13: 584–592 (1998). Burgess-Limerick, R. and A. Plooy et al., The Influence of computer monitor height on head and neck posture, Int J Ind Ergon, 23: 171–179 (1999a). Burgess-Limerick, R. and J. Shemmell et al., Wrist posture during pointing device use, Clin Biomech, 14: 280–286 (1999b).

1160    ◾    Occupational Ergonomics: Theory and Applications Burgess-Limerick, R. and J. Shemmell et al., Spontaneous transitions in lifting, Hum Movement Sci, 20: 549–562 (2001). Burgess-Limerick, R. and L. Steiner, Injuries associated with continuous miners, shuttle cars, loadhaul-dump, and personnel transport in New South Wales underground coal mines, Min Technol (TIMM A), 115: 160–168 (2006). Burgess-Limerick, R. and L. Steiner, Opportunities for preventing equipment related injuries in underground coal mines in the USA, Min Eng, October; 59(10): 20–32 (2007). Burgess-Limerick, R. and L. Straker et al., Participative ergonomics for manual tasks in coal mining, Int J Ind Ergon, 37: 145–155 (2007). Busse, M. and B. Bridger, Cost benefits of ergonomic intervention in a hospital: A preliminary study using Oxenburgh’s productivity model, Curationis, September; 20(3): 54–58 (1997). Cameron, C., Fatigue problems in modern industry, Ergonomics, November; 14(6): 713–720 (1971). Cameron, C., A theory of fatigue, Ergonomics, September; 16(5): 633–648 (1973). Caple, D., Emerging challenges to the ergonomics domain, Ergonomics, 51(1): 49–54 (2008). Carrivick, P.J. and A.H. Lee et al., Evaluating the effectiveness of a participatory ergonomics approach in reducing the risk and severity of injuries from manual handling, Ergonomics, June 22; 48(8): 907–914 (2005). Comans, T. and S. Brauer et al., A break-even analysis of a community rehabilitation falls prevention service, Aust NZ J Public Health, June; 33(3): 240–245 (2009). Commission of Occupational Safety and Health of Western Australia, Code of practice for manual handling, State Government of Western Australia, Perth, Western Australia, Australia, 2000. Commission of Occupational Safety and Health of Western Australia, Code of practice for the prevention of falls at workplaces, Government of Western Australia, Perth, Western Australia, Australia, 2004. Cook, C. and R. Burgess-Limerick et al., The prevalence of neck and upper extremity musculoskeletal symptoms in computer mouse users, Int J Ind Ergon, 26: 347–356 (2000). Cook, C. and R. Burgess-Limerick et al., The effect of upper extremity support on upper extremity posture and muscle activity during keyboard use, Appl Ergon, 35: 285–292 (2004a). Cook, C. and R. Burgess-Limerick et al., The effect of wrists rests during keyboard use with forearm support, Int J Ind Ergon, 33: 463–472 (2004b). Cook, C. and R. Burgess-Limerick, The effect of forearm support on musculoskeletal discomfort during call centre work, Appl Ergon, 35: 337–342 (2004). Cooper, A. and L. Straker, Mouse versus keyboard use: A comparison of shoulder muscle load, Int J Ind Ergon, 22: 351–357 (1998). Cromie, J.E. and V.J. Robertson et al., Work-related musculoskeletal disorders in physical therapists: Prevalence, severity, risks, and responses, Phys Ther, April; 80(4): 336–351 (2000). Cromie, J.E. and V.J. Robertson et al., Work-related musculoskeletal disorders and the culture of physical therapy, Phys Ther, May; 82(5): 459–472 (2002). Cromie, J.E. and V.J. Robertson et al., Physical therapists who claimed workers’ compensation: A qualitative study, Phys Ther, December; 83(12): 1080–1089 (2003). Cumming, R.W., Human information processing under varying task demand, Ergonomics, September; 16(5): 581–586 (1973). Dankaerts, W. and P. O’Sullivan et al., Altered patterns of superficial trunk muscle activation during sitting in nonspecific chronic low back pain patients: Importance of subclassification, Spine, 31(17): 2017–2023 (2006a). Dankaerts, W. and P.B. O’Sullivan et al., Inter-examiner reliability of a classification method for nonspecific chronic low back pain patients with motor control impairment, Man Ther, 11: 28–39 (2006b).

Overview of Ergonomics in Australia    ◾    1161   David Caple and Associates Pty Ltd, Physical safety in small and medium-sized enterprises (SME’s): Strategies for addressing the special needs of these organisations and their employees, National Occupational Health and Safety Commission, Canberra, Australian Capital Territory, Australia, Commonwealth of Australia, 2003. Day, L. and G. Rechnitzer, Safe tractor access platforms: From guidance material to implementation, J Agric Saf Health, August; 10(3): 197–209 (2004). Day, L. and D. Voaklander et al., Risk factors for work related injury among male farmers, Occup Environ Med, May; 66(5): 312–318 (2009). Department of Health Safety and Welfare of Western Australia, Strategies to reduce the risk of back strain in nursing homes, Government of Western Australia, Perth, Western Australia, Australia, 1989. Department of Health Safety and Welfare of Western Australia, Strain injuries to council workers: Reducing the risks, Government of Western Australia, Perth, Western Australia, Australia, 1991. Department of Health Safety and Welfare of Western Australia, Manual handling in the meat industry: Reducing the risks, Government of Western Australia, Perth, Western Australia, Australia, 1992. Department of Mines and Petroleum, Hazardous manual tasks [http://www.dmp.wa.gov.au/7221. aspx#7225]. Accessed October 2009. Driscoll, T.R. and R.J. Mitchell et al., Unintentional fatal injuries arising from unpaid work at home, Inj Prev, March; 9(1): 15–19 (2003). Duncan, J. and D. Ferguson, Keyboard operating posture and symptoms in operating, Ergonomics, September; 17(5): 651–662 (1974). Elford, W. and L. Straker et al., Patient handling with and without slings: An analysis of the risk of injury to the lumbar spine, Appl Ergon, 31: 185–200 (2000). Engkvist, I.L., Evaluation of an intervention comprising a no lifting policy in Australian hospitals, Appl Ergon, March; 37(2): 141–148 (2006). Engkvist, I.L., Nurse’s expectations, experiences and attitudes towards the intervention of a ‘no lifting policy’, J Occup Health and Saf—Aust NZ, 49: 294–304 (2007). Evans, O.M. and K. Patterson, Predictors of neck and shoulder pain in non-secretarial computer users, Int J Ind Ergon, 26: 357–365 (2000). Ferguson, D., Ergonomics in Australia, Med J of Aust, January 4; 1(1): 30–33 (1969). Ferguson, D., Repetition injuries in process workers, Med J Aust, August 21; 2(28): 408–412 (1971). Ferguson, D., Ergonomics and the quality of living, Appl Ergon, June; 3(2): 70–74 (1972). Ferguson, D., A study of occupational stress and health, Ergonomics, September; 16(5): 648–664 (1973). Ferguson, D. and J. Duncan, Keyboard design and operating posture, Ergonomics, November; 17(6): 731–744 (1974). Fisher, A.J. and R.R. Hall, The influence of car frontal design on pedestrian accident trauma, Accid Anal Prevent, 4: 47–58 (1972). Fisher, A.J. and R.R. Hall, The effect on vision of terminations and isolated lengths of fixed lighting, Aust Road Res, 5: 34–39 (1973). Fisher, A.J. and R.R. Hall, Road lighting levels based on detection of change of visual angle, Light Res Technol, 8(4): 187–194 (1976). Fisher, A.J. and R.R. Hall, The effect of presence lights on the detection of change of vehicle headway, Aust Road Res, 8(2): 13–16 (1978). Fisher, A.J. and R.R. Hall, Aids in night driving, Aust J Optomet, 65(5): 194–195 (1982). Fisher, A.J. and R.R. Hall, The lighting of curves on arterial roads, Light Res Technol, 17(3): 129–137 (1985a). Fisher, A.J. and R.R. Hall, The lighting of curves, Providing Visibility and Visual Guidance to the Road User, Transportation No. 297, pp. 27–28, 1985b.

1162    ◾    Occupational Ergonomics: Theory and Applications Fisher, A.J. and R.R. Hall, Luminance, uniformity and glare in road lighting—Some more equal than others, Aust Road Res, 16(3): 184–193 (1986). Fraser, C.E. and K.B. Smith et al., Farming and mental health problems and mental illness, Int J Soc Psychiatry, December; 51(4): 340–349 (2005). Greig, A. and L. Straker et al., Cervical erector spinae and upper trapezius activity in children using desktop and laptop computers, Physiotherapy, 91(2): 119–126 (2005). Grundgeiger, T. and P. Sanderson, Interruptions in healthcare: Theoretical views, Int J Med Inform, 78: 293–307 (2009). Gun, R.T. and G.M. Budd, Effects of thermal, personal and behavioural factors on the physiological strain, thermal comfort and productivity of Australian shearers in hot weather, Ergonomics, July; 38(7): 1368–1384 (1995). Gun, R.T. and P.T. Jezukaitis, RSI: A perspective from its birthplace, Occup Med, January–March; 14(1): 81–95, (1999). Hall, R.R., CIE standard luminance program for the calculation of luminance in road lighting design— Users reference manual, Australian Road Research Board, Vermont, Victoria, Australia, 1976. Hall, R.R., The delineation of rural roads and curve negotiation at night, Australian Road Research Board, Vermont South, Victoria, Australia, 1979. Hall, R.R., The design and implementation of fixed lighting for arterial roads and freeways, Australian Road Research Board, Vermont South, Victoria, 1980. Hall, R.R., Usability and product design, Ergonomics, Usability and Product Development, P. Jordan and W. Green (eds.), Taylor & Francis, London, U.K., pp. 85–91, 1998. Hall, R.R., Prototyping for usability of new technology, Int J Hum Comput Stud, 55(4): 485–501 (2001). Hall, R.R. and A.J. Fisher, Some factors affecting the trauma of pedestrians involved in road accidents, Med J Aust, 1(7): 313–317 (1972). Hall, R.R. and A.J. Fisher, Measures of visibility and visual performance in road lighting, Australian Road Research Board, Vermont South, Victoria, Australia, 1978. Hall, R.R. and A.J. Fisher, Freeway lighting: Analysis of installation performance and cost, Australian Road Research Board, Vermont South, Victoria, Australia, 1980. Hall, W. and L. Morrow, Repetition strain injury: An Australian epidemic of upper limb pain, Soc Sci Med, 27(6): 645–649 (1988). Hall, R.R. and S. Zinser et al., The usability of time setting functions on small electronic consumer products—A test, Int J Cogn Ergono, 3(2): 101–114 (1998). Harris, C. and L. Straker, Survey of physical ergonomics issues associated with school children’s use of laptop computers, Int J Ind Ergon, 26: 337–347 (2000). Harvey, J.T. and J. Culvenor et al., An analysis of the forces required to drag sheep over various surfaces, Appl Ergon, 33(6): 523–531 (2002). Heads of Workplace Safety Authorities, Design 4 health: National manual handling campaign 2004, 2005, [http://www.hwsa.org.au/activities/activities-campaign_final_reports.aspx]. Accessed October 2009. Heads of Workplace Safety Authorities, National falls from heights in the heavy vehicle sector: Summary final report industry feedback, 2006, [http://www.hwsa.org.au/files/documents/ Activities%20-%20Campaign%20Final%20Reports/afba065a-6f71-4871-91d9-be5c7616ce34. pdf]. Accessed October 2009. Heads of Workplace Safety Authorities, Manual handling in manufacturing industry: HWSA final report, 2007, [http://www.hwsa.org.au/activities/activities-campaign_final_reports.aspx]. Accessed October 2009. Heads of Workplace Safety Authorities, “Safe steps—Manual tasks, slips and trips in hospitals: Final report, 2008a, [http://www.hwsa.org.au/activities/activities-campaign_final_reports.aspx]. Accessed October 2009.

Overview of Ergonomics in Australia    ◾    1163   Heads of Workplace Safety Authorities, Prevention of falls in construction 2008: HWSA final report, 2008b, [http://www.hwsa.org.au/activities/activities-campaign_final_reports.aspx]. Accessed October 2009. Hill, K.D. and D. LoGiudice et al., Effectiveness of balance training exercise in people with mild to moderate severity Alzheimer’s disease: Protocol for a randomised trial, BMC Geriatr, July 16; 9:29 (2009). Hitchens, P.L. and C.L. Blizzard et al., The incidence of race-day jockey falls in Australia, 2002–2006, Med J Aust, January 19; 190(2): 83–86 (2009). Horberry, T. and J. Anderson et al., Driver distraction: The effects of concurrent in-vehicle tasks, road environment complexity and age on driving performance, Accid Anal Prevent, 38(1): 185–191 (2006a). Horberry, T. and A. Gunatilaka et al., Intelligent transport systems for industrial mobile safety equipment, J Occup Health Saf—Aust NZ, 22(4): 323–334 (2006b). Horberry, T. and M. Regan et al., Airport ramp safety and intelligent transport systems, IET Intell Transp Sys, 1(4): 234–240 (2007). Hosking, S.G. and K.L. Young et al., The Effects of Text Messaging on Young Novice Driver Performance, Monash University Accident Research Centre, Melbourne, Victoria, Australia, 2006. Howie, A. and W. Macdonald et al., The ergonomics society of Australia, Ergonomics, 31(5): 751–760 (1988). Human Factors and Ergonomics Society of Australia, Membership, 2009a, [http://www.ergonomics. org.au/membership/cpe.aspx]. Accessed October 11, 2009. Human Factors and Ergonomics Society of Australia, 2009b, Professional development, [http:// www.ergonomics.org.au/events/professional_development.aspx]. Accessed October 11, 2009. Injury Control Council or Western Australia, Falls prevention. http://www.iccwa.org.au/falls-prevention (accessed October 2009). Innes, E. and L. Straker, A clinician’s guide to work-related assessments: 1. Purposes and problems, Work, 11: 183–189 (1998a). Innes, E. and L. Straker, A clinician’s guide to work-related assessments: 2. Design problems, Work, 11: 191–206 (1998b). Innes, E. and L. Straker, A clinician’s guide to work-related assessments: 3. Administration and interpretation problems, Work, 11: 207–219 (1998c). Innes, E. and L. Straker, Reliability of work-related assessments, Work, 13: 107–124 (1999a). Innes, E. and L. Straker, Validity of work-related assessments, Work, 13: 125–152 (1999b). Innes, E. and L. Straker, Workplace assessments and functional capacity evaluations: Current practices of therapists in Australia, Work, 18: 51–66 (2002a). Innes, E. and L. Straker, Strategies used when conducting work related assessments, Work, 19: 149– 166 (2002b). Innes, E. and L. Straker, Workplace assessments and functional capacity evaluations: Current beliefs of Australian therapists, Work, 20(3): 225–236 (2003a). Innes, E. and L. Straker, Attributes of excellence in work related assessments, Work, 20(1): 63–76 (2003b). International Ergonomics Association, IEA federated societies, [http://www.iea.cc/browse. php?contID=technical_committees_home]. Accessed November 20, 2009. Ireland, D.C., Repetition strain injury: The Australian experience—1992 update, J Hand Surg Am, May; 20A(3 Pt 2): S53–S56 (1995). Ireland, D.C., Australian repetition strain injury phenomenon, Clin Orthop Relat Res, June; (351): 63–73 (1998). Johnstone, R., Ed., Occupational Health and Safety Law and Policy: Text and Materials, Lawbook Co., Sydney, New South Wales, Australia, 2004. Judd, F. and H. Jackson et al., Understanding suicide in Australian farmers, Soc Psychiatry Psychiatr Epidemiol, January; 41(1): 1–10 (2006). King, J. and P. Foreman et al., Back injuries among nurses: Prevalence, risk factors and prevention, Aust J Rehabil Counsell, 7: 106–114 (2001).

1164    ◾    Occupational Ergonomics: Theory and Applications Kunelius, A. and S. Darzins et al., Development of normative data for hand strength and anthropometric dimensions in a population of automotive workers, Work: J Preven, Assess Rehabil, 28: 267–278 (2007). La Trobe University, Postgraduate coursework programs in occupational health, safety and ergonomics—Distance mode, [http://www.latrobe.edu.au/ergonomics/PG_OHSE.html]. Accessed November 2009. Lacherez, P. and E. Seah et al., Overlapping medical alarms are almost indiscriminable, Hum Factors, 49(4): 637–645 (2007). Lane, J.C., Human engineering: A new technology, Med J Aust, July 4; 2(1): 7–10 (1953). Legge, J. and R. Burgess-Limerick, Reliability of the jobfit system pre-employment functional assessment tool, Work, 28: 299–312 (2007). Lenné, M. and K. Ashby et al., Analysis of general aviation crashes in Australia using the human factors analysis and classification system, Int J Aviat Psychol, 18: 340–352 (2008a). Lenné, M. and K. Ashby, Characteristics on non-fatal general aviation crashes in Australia: Insights from insurance data, Hum Factor Aero Saf, 6(4): 395–407 (2008). Lenné, M. and C. Mulvihill et al., Detection of emergency vehicles: Driver responses to advanced warning in a driving simulator, Hum Factors, 50(1): 135 (2008b). Li, X. and P. Sanderson et al., Evaluating functional displays for hydropower system: Model-based guidance of scenario design, Cogn Technol Work, 8(4): 269–282 (2006). Lindgaard, G. and D. Caple, A case study in iterative keyboard design using participatory design techniques, Appl Ergon, February; 32(1): 71–80 (2001). Liu, D. and T. Grundgeiger et al., Interruptions and blood transfusion checks: Lessons from the simulated operating room, Anesth Analg, 107(1): 219–222 (2009a). Liu, D. and S. Jenkins et al., Monitoring with head-mounted displays: Performance and safety in a full-scale simulator and part-task trainer, Anesth Analg, 109(4): 1135–1146 (2009b). Liu, D. and S. Jenkins et al., Patient monitoring with head-mounted displays, Curr Opin Anaesthesiol, 22(6): 796–803 (2009c). Loft, S. and P. Sanderson et al., Modeling and predicting mental workload in en route air traffic control: Critical review and broader implications, Hum Factors, 49(3): 376–399 (2007). Ltd, U.P., Issues associated with force and weight limits and associated threshold limit values in the physical handling work environment, N. O. H. a. S. Commission, Canberra, Australian Capital Territory, Australia, Commonwealth of Australia, 2003. Macdonald, W.A., The impact of job demands and workload on stress and fatigue, Aust Psycholo, 38(2): 102–117 (2003). Macdonald, W., Workload, stress and psychosocial factors as hazards for musculoskeletal disorders, J Occup Health and Saf—Aust NZ, 20(1): 37–47 (2004). Macdonald, W., Managing workloads to optimise performance, health and wellbeing, International Encyclopedia of Ergonomics and Human Factors, W. Karwowski (ed.), Taylor & Francis, Boca Raton, FL, pp. 2170–2174, 2006a. Macdonald, W., Workload, performance, health and wellbeing: A conceptual framework, International Encyclopedia of Ergonomics and Human Factors, W. Karwowski (ed.), Taylor & Francis, Boca Raton, FL, pp. 2794–2799, 2006b. Macdonald, W. and S. Bendak, Effects of workload level and 8- versus 12-h workday duration on test battery performance, Int J Ind Ergon, 26(3): 399–416 (2000). Macdonald, W. and K. Munk, Determinants of work-related stress in physical handling work environments: Issues Paper 6, Review of the National Manual Handling Standard, Codes of practice and associated guidance materials, N. O. H. S. Commission, Canberra, Australian Capital Territory, Australia, Commonwealth Government of Australia, p. 55, 2003. Mackenzie, L., Perceptions of health professionals about effective practice in falls prevention, Disabil Rehabil, 31(24): 2005–2012 (2009).

Overview of Ergonomics in Australia    ◾    1165   Mackenzie, L. and J. Byles et al., Longitudinal study of the home falls and accidents screening tool in identifying older people at increased risk of falls, Australas J Ageing, June; 28(2): 64–69 (2009). Martin, E., Work-related musculoskeletal disorders in Victorian occupational therapists, 22nd National Conference, OT Australia, Melbourne, Victoria, Australia, 2003. Mayman, S.C., Getting the dynamics right, [http://www.wairc.wa.gov.au/Files/DiscussionPapers/ National%20Safety%20Summit%20(presentation).ppt]. Accessed October 11, 2009. McPhee, B., Ergonomics for the Control of Sprains and Strains in Mining, Worksafe Australia, Canberra, Australian Capital Territory, Australia, 1993. McPhee, B., Ergonomics in mining, Occup Med (Lond), August; 54(5): 297–303 (2004). Mcphee, B. and G. Foster et al., Bad Vibrations: A Handbook on Whole-Body Vibration Exposure in Mining, The Joint Coal Board Health and Safety Trust, Sydney, New South Wales, Australia, 2001. McShane, C.J. and F. Quirk, Mediating and moderating effects of work-home interference upon farm stresses and psychological distress, Aust J Rural Health, October; 17(5): 244–250 (2009). Memisevic, R. and P. Sanderson et al., Investigating human-system interaction with an integrated hydropower and market system simulator, IEEE Trans Power Syst, 22(2): 762–769 (2007). Mon-Williams, M. and R. Burgess-Limerick et al., Vertical gaze direction and postural adjustment: An extension of the heuer model, J Exp Psychol Appl, 5: 35–53 (1999). Murphy, G. and J. Athanasou et al., Job satisfaction and organisational citizenship behaviour: A study of Australian human-service workers, J Manag Psychol, 17: 287–297 (2002). Murphy, D.G. and R. Hall et al., Robotic technology in surgery: Current status in 2008, ANZ J Surg, December; 78(12): 1076–1081 (2008). Naikar, N. and D. Drumm et al., Designing teams for first-of-a-kind, complex systems using the initial phases of cognitive work analysis: Case study, Hum Factors, 45(2): 202–217 (2003). Naikar, N. and P.M. Sanderson, Work domain analysis for training system definition and acquisition, Int J Aviat Psychol, 9(3): 271–290 (1999). Naikar, N. and P. Sanderson, Evaluating system design proposals with work domain analysis, Hum Factors, 43(4): 529–542 (2001). National Occupational Health and Safety Commission, National code of practice for the prevention of occupational overuse syndrome, Australian Government Publishing Service, Canberra, Australian Capital Territory, Australia, 1994. National Occupational Health and Safety Commission, National code of practice for manual handling, Australian Government Publishing Agency, Canberra, Australian Capital Territory, Australia, 2005. National Research Centre for OSH Regulation, About occupational health and safety regulation in Australia, [http://ohs.anu.edu.au/ohs/index.php]. Accessed November 2009. NOHSC Office Safe Design Team, The role of design decision-makers in addressing the risk of manual handling injury in the workplace, National Occupational Health and Safety Commission, Canberra, Australian Capital Territory, Australia, Commonwealth of Australia, 2003. NSW Health, Zero tolerance: Response to violence in the NSW health workplace, North Sydney, New South Wales, Australia, NSW Department of Health, 2003. O’Connor, P., Work related spinal cord injury, Australia 1986–1997, Inj Prev, March; 7(1): 29–34 (2001). O’Sullivan, P. and W. Dankaerts et al., Lumbopelvic kinematics and trunk muscle activity during sitting on stable and unstable surfaces, J Orthop Sports Phys Ther, 36: 19–25 (2006). Oxenburgh, M.S., Ergonomics: Ron Cumming memorial lecture. Ergonomics, economics, and ethics, J Occup Environ Hyg, November; 1(11): D126–D128 (2004). Oxenburgh, M.S. and H.H. Guldberg, The economic and health effects on introducing a safe manual handling code of practice, Int J Ind Ergon, 12: 241–253 (1993).

1166    ◾    Occupational Ergonomics: Theory and Applications Oxenburgh, M. and P. Marlow, The productivity assessment tool: Computer-based cost benefit analysis model for the economic assessment of occupational health and safety interventions in the workplace, J Saf Res, 36(3): 209–214 (2005). Oxenburgh, M.S. and S.A. Rowe et al., Repetition strain injury in keyboard operators, J Occup Health and Saf, 1(2): 106–112 (1985). Ozanne-Smith, J. and J. Guy et al., The Relationship between Slips, Trips and Falls and the Design and Construction of Buildings, Monash University Accident Research Centre, Monash University, Melbourne, Victoria, Australia, 2008. Patkin, M., Ergonomic aspects of surgical dexterity, Med J Aust, October 21; 2(17): 775–777 (1967). Patkin, M., Ergonomics applied to the practice of microsurgery, Aust NZ J Surg, June; 47(3): 320–329 (1977). Patkin, M., Ergonomics and the operating microscope, Adv Ophthalmol, 37: 53–63 (1978). Patkin, M., Ergonomics in microsurgery, Aust NZ J Obstet Gynaecol, August; 21(3): 134–136 (1981). Patkin, M. and L. Isabel, Ergonomics, engineering and surgery of endosurgical dissection, J R Coll Surg Edinb, April; 40(2): 120–132 (1995). Peterson, C.L., Work factors and stress: A critical review, Int J Health Serv, 24(3): 495–519 (1994). Peterson, C., Stress amongst the healthcare workforce, J Occup Health Saf, Austr NZ, 19(1): 49–58 (2003). Phillips, J.G. and J.W. Meehan et al., Effects of cursor orientation and required precision upon positioning movements on computer screens, Int J Hum Comput Interact, 15(3): 379–389 (2003a). Phillips, J.G. and T.J. Triggs, Cursor control device characteristics, Aust J Inform Sys, 7(2): 115–119 (2000). Phillips, J.G. and T.J. Triggs et al., Cursor orientation and computer screen positioning movements, Hum Factors, 43: 435–441 (2001). Phillips, J.G. and T.J. Triggs, Characteristics of cursor trajectories controlled by the computer mouse, Ergonomics, 44: 527–536 (2001). Phillips, J.G. and T.J. Triggs et al., Conflicting directional and locational cues afforded by arrowhead cursors in graphical user interfaces, J Exp Psychol Appl, 9(2): 75–87 (2003b). Provins, K.A., Handedness and motor skill, Med J Aust, September 2; 2(10): 468–470 (1967). Provins, K.A., The specificity of motor skill and manual asymmetry: A review of the evidence and its implications, J Mot Behav, June; 29(2): 183–192 (1997). Provins, K.A. and C.R. Bell et al., The cross-cultural measurement of perceptual and motor skills in relation to human adaptation, Hum Biol, December; 40(4): 484–493 (1968). Provins, K.A. and R.S. Clarke, The effect of cold on manual performance, J Occup Med, April; 2: 169–176 (1960). Provins, K.A. and P. Cunliffe, Motor performance tests of handedness and motivation, Percept Mot Skills, August; 35(1): 143–150 (1972a). Provins, K.A. and P. Cunliffe, The relationship between E.E.G. activity and handedness, Cortex, June; 8(2): 136–146 (1972b). Provins, K.A. and P. Cunliffe, The reliability of some motor performance tests of handedness, Neuropsychologia, July; 10(2): 199–206 (1972c). Provins, K.A. and D.J. Glencross, Handwriting, typewriting and handedness, Q J Exp Psychol, August; 20(3): 282–289 (1968). Provins, K.A. and D.J. Glencross et al., Thermal stress and arousal, Ergonomics, September; 16(5): 623–631 (1973). Provins, K.A. and J. Magliaro, The measurement of handedness by preference and performance tests, Brain Cogn, July; 22(2): 171–181 (1993). Quintner, J., The pain of ‘RSI’. A historical perspective, Aust Fam Physician, August; 18(8): 1003– 1006, 1008–1009 (1989).

Overview of Ergonomics in Australia    ◾    1167   Ranelli, S. and L. Straker et al., Prevalence of playing-related musculoskeletal symptoms and disorders in children learning instrumental music, Med Probl Perform Art, 23: 178–185 (2008). Regan, M., Preventing traffic accidents by mobile phone users, Med J Aust, 185: 11–12 (2006). Regan, M. and K. Stephan et al., The effect on driver workload, attitudes and acceptability of invehicle intelligent transport systems: Selected final results from the TAC safecar project, J Aust Coll Road Saf, 18(1): 30–36 (2007a). Regan, M. and K. Young et al., Effects on driving performance of in-vehicle intelligent transport systems: Final results of the Australian TAC safecar project, J Australas Coll Road Saf, 18(1): 23–30 (2007b). Retsas, A. and J. Pinikahana, Manual handling activities and injuries among nurses: An Australian hospital study, J Adv Nurs, April; 31(4): 875–883 (2000). Robens, A., Safety and health at work, Vol. 1, London, U.K., Report of the Committee, pp. 1970–1972 (1972). Roelofs, A. and L. Straker, The experience of musculoskeletal discomfort amongst bank tellers who just sit, just stand or sit and stand at work, Ergonomics SA, 14(2): 11–29 (2002). Safe Work Australia, OHS and ageing surveillance alert, Canberra, Australian Capital Territory, Australia, Commonwealth of Australia, 2005. Safe Work Australia, Research on the prevention of work-related musculoskeletal disorders stage 1—Literature Review 2006, Canberra, Australian Capital Territory, Australia, Commonwealth of Australia, 2006a. Safe Work Australia, Work-related fatigue- summary of recent indicative research, Canberra, Australian Capital Territory, Australia, Commonwealth of Australia, 2006b. Safe Work Australia, Work-related mental health disorders in Australia, Canberra, Australian Capital Territory, Australia, Commonwealth of Australian, 2006c. Safe Work Australia, Work-related musculoskeletal disorders in Australia, Canberra, Australian Capital Territory, Australia, Commonwealth of Australia, 2006d. Safe work Australia, Safe work Australia council media release June 10, 2009a, [http://www. safeworkaustralia.gov.au/swa/NewsEvents/MediaReleases/SafeWorkAustraliaCouncilMedia Release10June2009.htm]. Accessed October 2009. Safe Work Australia, Sizing up Australia: How contemporary is the anthropometric data Australian designers use, Canberra, Australian Capital Territory, Australia, Commonwealth of Australia, 2009b. Safe Work Australia, Manual handling risks associated with the care, treatment and transportation of bariatric (severely obese) patients in Australia, Canberra, Australian Capital Territory, Australia, Commonwealth of Australia, 2009c. Salmon, P.M. and M.A. Regan et al., Human error and road transport: Phase two—A framework for an error tolerant road transport system, Monash University Accident Research Centre, Melbourne, Victoria, Australia, Vol. 257, p. 53, 2006. Salmon, P. and M. Regan et al., Work domain analysis and intelligent transport systems: Implications for vehicle design, Int J Vehi Des, Spec Iss Hum Factor Vehi Des, 45(3): 426–448 (2007). Salmon, P.M. and N.A. Stanton et al., Measuring situation awareness in complex systems: Comparison of measures study, Int J Ind Ergon, 39: 490–500 (2009). Sanderson, P.M., Cognitive work analysis, HCI Models, Theories, and Frameworks: Toward an Interdisciplinary Science, J. Carroll (ed.), Morgan-Kaufmann, New York, 2003. Sanderson, P., The multimodal world of medical monitoring displays, Appl Ergon, 37(4): 501–512 (2006). Sanderson, P. and J. Crawford et al., Visual and auditory attention in patient monitoring: A formative analysis, Cogn Technol Work, 6(3): 172–185 (2004). Sanderson, P.M. and D. Liu et al., Auditory displays in anaesthesiology, Curr Opin Anaesthesiol, 22(6): 788–795 (2009).

1168    ◾    Occupational Ergonomics: Theory and Applications Sanderson, P. and A. Pipingas et al., Process monitoring and configural display design: A neuroimaging study, Theoretical Iss Ergon Sci, 4(2): 151–174 (2003). Sanderson, P. and N. Tosh et al., Effects of ambient music on simulated anaesthesia monitoring with visual and auditory displays, Anaesthesia, 60(11): 1073–1078 (2005a). Sanderson, P. and M. Watson et al., Advanced patient monitoring displays: Tools for continuous informing, Anesth Analg, 101(1): 161–168 (2005b). Sanderson, P.M. and M.O. Watson et al., Advanced auditory displays and head mounted displays: Advantages and disadvantages for monitoring by the distracted anesthesiologist, Anesth Analg, 106(6): 1787–1797 (2008). Sanderson, P. and A. Wee et al., Learnability and discriminability of melodic medical equipment alarms, Anaesthesia, 61: 142–147 (2006). Scutter, S. and K.S. Türker et al., Headaches and neck pain in farmers, Aust J Rural Health, 5(1): 2–5 (1997). Seagull, F.J. and P.M. Sanderson, Anesthesia alarms in surgical context: An observational study, Hum Factors, 43(1): 66–77 (2001). Shaw Idea, Digging Deeper Wran Consultancy Project, NSW Department of Primary Industries, Orange, NSW, New South Wales Government, 2007. Shepherd, G.W. and R.J. Kahler et al., Ergonomic design interventions—A case study involving portable ladders, Ergonomics, February 22; 49(3): 221–234 (2006). Stain, H.J. and B. Kelly et al., Social networks and mental health among a farming population, Soc Psychiatry Psychiatr Epidemiol, October; 43(10): 843–849 (2008). Stanton, N.A. and P.M. Salmon et al., Predicting pilot error: Testing a new method and a multimethods and analysts approach, Appl Ergon, 40(3): 464–471 (2009). State Government Victoria, Victorian nurses back prevention programme: Evaluation report 2002, Department of Human Services, Victorian Government, Melbourne, Victoria, Australia, 2002. State Government Victoria, Preventing falls in Victoria 2007–2012: Discussion paper. D. o. H. S. Aged Care Branch, State Government Victoria, Melbourne, Victoria, Australia, 2007. Stevenson, M.G. and N. Coleman et al., Assessment, re-design and evaluation of changes to the driver’s cab in a suburban electric train, Appl Ergon, October; 31(5): 499–506 (2000). Stevenson, R.S. and J.G. Phillips et al., Mouse and display tablets as cursor control devices, Int J Pattern Recogn Artif Intell, 18: 1–12 (2004). Straker, L. and A. Briggs et al., The effect of individually adjusted workstations on upper quadrant posture and muscle activity in school aged children, Work, 18: 239–248 (2002). Straker, L. and R. Burgess-Limerick et al., A randomized and controlled trial of a participative ergonomics intervention to reduce injuries associated with manual tasks: Physical risk and legislative compliance, Ergonomics, 47(2): 166–188 (2004). Straker, L. and R. Burgess-Limerick et al., Towards evidence based guidelines for wise use of computers by children, Int J Ind Ergon, 36(12): 1045–1053 (2006). Straker, L. and R. Burgess-Limerick et al., Children’s head, neck and upper limb posture and muscle activity at different computer and paper display heights, Hum Factors, 50: 49–61 (2008a). Straker, L. and R. Burgess-Limerick et al., The impact of computer display height and desk design on 3D posture during information technology work by young adults, J Electromyogr Kinesiol, April; 18(2): 336–349 (2008b). Straker, L. and R. Burgess-Limerick et al., The effect of forearm support on children’s head, neck and upper limb posture and muscle activity during computer use, J Electromyo Kinesiol, October; 19(5): 965–974 (2009a). Straker, L. and R. Burgess-Limerick et al., The influence of desk and display design on posture and muscle activity variability whilst performing information technology tasks, Appl Ergon, September; 40(5): 852–859 (2009b).

Overview of Ergonomics in Australia    ◾    1169   Straker, L. and B.A. Maslen et al., Children have less variable postures and muscle activities when using new electronic information technology compared with old paper based information technology, J Electromyogr Kinesiol, 19: e132–e143 (2009c). Straker, L. and C. Pollock et al., Principles for the wise use of computers by children, Ergonomics, 52(11): 1386–1401 (2009d). Straker, L. and C. Cain, Psychophysical and physiological comparison of squat and semi-squat lifting by young males, Occup Ergon, 1: 17–26 (1999). Straker, L.M. and J. Coleman et al., A comparison of posture and muscle activity during tablet computer, desktop computer and paper use by young children, Ergonomics, 51: 540–555 (2008c). Straker, L. and P. Duncan, Psychophysical and psychological comparison of squat and stoop lifting by young females, Aust J Physiother, 46: 27–32 (2000). Straker, L. and K. Jones et al., A comparison of the postures assumed when using laptop computers and desktop computers, Appl Ergon, 28: 263–268 (1997a). Straker, L. and S.E. Mathiassen, Increased physical work loads in modern work–a necessity for better health and performance, Ergonomics, October; 52(10): 1215–1225 (2009). Straker, L. and K. Mekhora, An evaluation of visual display unit placement by electromyography, posture, discomfort and preference, Int J Ind Ergon, 26: 335–336 (2000). Straker, L. and P.B. O’Sullivan et al., Computer use and habitual spinal posture in Australian adolescents, Public Health Rep, 122(5): 634–643 (2007). Straker, L. and C. Pollock et al., The effect of shoulder posture on performance: Discomfort and muscle fatigue whilst working on a visual display unit, Int J Ind Ergon, 21: 1–10 (1997b). Straker, L. and C. Pollock et al., The impact of computer display height and desk design on muscle activity during information technology work by young adults, J Electromyogr Kinesiol, Aug; 18(4): 606–617 (2008d). Straker, L. and R. Skoss et al., Effect of visual display height on modelled upper and lower cervical gravitational moment, muscle capacity and relative strain, Ergonomics, February; 52(2): 204–221 (2009e). Straker, L. and M. Stevenson et al., A comparison of risk assessment of single and combination manual handling tasks: 2 Discomfort, rating of perceived exertion and heart rate measures, Ergonomics, 40: 656–669 (1997a). Straker, L. and M. Stevenson et al., A comparison of risk assessment of single and combination manual handling tasks: 3 Biomechanical measures, Ergonomics, 40: 708–728 (1997b). Szeto, G. and L. Straker et al., A field comparison of neck and shoulder postures in symptomatic and asymptomatic office workers, Appl Ergon, 33: 75–84 (2002). Szeto, G. and L. Straker et al., A comparison of symptomatic and asymptomatic office workers performing monotonous keyboard work—1: Neck and shoulder muscle recruitment patterns, Man Ther, 10(4): 270–280 (2005a). Szeto, G. and L. Straker et al., A comparison of symptomatic and asymptomatic office workers performing monotonous keyboard work—2: Neck and shoulder kinematics, Man Ther, 10(4): 281–291 (2005b). Szeto, G. and L. Straker et al., EMG median frequency changes in the neck-shoulder stabilizers of symptomatic office workers when challenged by different physical stressors, J Electromyogr Kinesiol, 15(6): 544–555 (2005c). Szeto, G.P.Y. and L.M. Straker et al., The effects of typing speed and force on motor control in symptomatic and asymptomatic office workers, Int J Ind Ergon, 35(9): 429–444 (2005d). Thompson, M. and P.M. Sanderson, Multisensory integration with a head-mounted display: Sound delivery and self-motion, Hum Factors, 50(5): 789–800 (2008). Torma-Krajewski, J. and C. Hipes et al., Ergonomics interventions at vulcan materials company, Min Eng, December; 59(11): 54–58 (2007).

1170    ◾    Occupational Ergonomics: Theory and Applications Tuckwell, N. and L. Straker et al., Test retest reliability on nine tasks of the physical work performance evaluation, Work, 19: 243–253 (2002). Uniquest Pty Ltd., Issues associated with force and weight limits and associated threshold limit values in the physical handling work environment, National Occupational Health and Safety Commission, Canberra, Australian Capital Territory, Australia, Commonwealth of Australia, 2003. UniSA, ADAPT project (Australian defence anthropometric personnel testing), [http://www.unisa. edu.au/adapt/default.asp]. Accessed October 2009. University of Queensland, Graduate certificate in ergonomics, [http://www.uq.edu.au/study/ program.html?acad_prog=5281]. Accessed 2009. Victorian WorkCover Authority, Code of practice for manual handling, State Government of Victoria, Melbourne, Victoria, Australia, 2000. Watson, M. and W.J. Russell et al., Anaesthesia monitoring, alarm proliferation, and ecological interface design, Aust J Inform Syst, 7(2): 109–114 (2000). Watson, M. and P. Sanderson et al., Tailoring reveals information requirements: The case of anaesthesia alarms, Interact Comput, 16: 271–293 (2004). Watson, M. and P. Sanderson, Sonification helps eyes-free respiratory monitoring and task timesharing, Hum Factors, 46(3): 497–517 (2004). Watson, M. and P. Sanderson, Designing for attention with sound: Challenges and extensions to ecological interface design, Hum Factors, 49(2): 331–346 (2007). Wee, A. and P. Sanderson, Are melodic medical equipment alarms easily learned, Anesth Analg, 106(2): 501–508 (2008). Weeks, K. and C.L. Peterson et al., Stress and the workplace: The medical scientists’ experience, Lab Ind, 11(3): 95–120 (2000). Welford, A.T., Perceptual selection and integration, Ergonomics, January; 13(1): 5–23 (1970). Welford, A.T., What is the basis of choice reaction-time, Ergonomics, November; 14(6): 679–693 (1971). Welford, A.T., Stress and performance, Ergonomics, September; 16(5): 567–580 (September 1973). Welford, A.T., Ergonomics: Where have we been and where are we going: I, Ergonomics, May; 19(3): 275–286 (1976). Welford, A.T., Mental work-load as a function of demand, capacity, strategy and skill, Ergonomics, March; 21(3): 151–167 (1978). Welford, A.T., Preventing adverse changes of work with age, Int J Aging Hum Dev, 27(4): 283–291 (1988a). Welford, A.T., Reaction time, speed of performance, and age, Ann NY Acad Sci, 515: 1–17 (1988b). Welford, A.T., The ergonomic approach to social behaviour, Ergonomics, September; 9(5): 357–369 (1996). Wigglesworth, E.C., Ergonomics, safety and railway level crossings, Ergon Aust, 21(4): 4–13 (2008). WorkCover Corporation of South Australia, Code of practice for manual handling adelaide, South Australian Government, Adelaide, South Australia, Australia, 1990. WorkCover New South Wales, Preventing slips, trips and falls: Guide, WorkCover NSW, Gosford, New South Wales, Australia, 2006. Workplace Health and Safety Queensland, Manual tasks code of practice 2000, DOJA AttorneyGeneral, Queensland Government, Brisbane, Queensland, Australia, 2000. Workplace Health and Safety Queensland, Occupational stress tip sheets: Risk assessment approach, [http://www.deir.qld.gov.au/workplace/resources/pdfs/occstress-riskmgt.pdf]. Accessed October 2009. Workplace Health and Safety Queensland, Slips, trips, and falls prevention, D. o. E. a. I. Relations, Queensland Government, Brisbane, Queensland, Australia, 2007.

Overview of Ergonomics in Australia    ◾    1171   WorkSafe, W.A., Preventing manual handling injuries in the workplace, [http://www.commerce. wa.gov.au/WorkSafe/Content/Safety_Topics/Manual_handling/Preventing_manual_ handling_inj.html]. Accessed October 2009. WorkSafe, Victoria, Safety by design: Eliminating manual handling injuries in road transport, State Government Victoria, Melbourne, Victoria, Australia, 2001. WorkSafe, Victoria, Manual handling solutions in the textile industry, State Government Victoria, Melbourne, Victoria, Australia, 2002. WorkSafe, Victoria, Manual handling solutions in the sawmilling industry, State Government Victoria, Melbourne, Victoria, Australia, 2005. WorkSafe, Victoria, A guide to manual handling in the food industry, State Government Victoria, Melbourne, Victoria, Australia, 2006a. WorkSafe, Victoria, Slips, trips, and falls checklist, State Government Victoria, Melbourne, Victoria, Australia, 2006b. Worksafe, Victoria, Stresswise-preventing work-related stress, State Government Victoria, Melbourne, Victoria, Australia, 2007a. WorkSafe, Victoria, A guide to designing workplaces for safer handling of people, State Government Victoria, Melbourne, Victoria, Australia, 2007b. WorkSafe, Victoria, A guide to safety in the metal fabrication industry, State Government Victoria, Melbourne, Victoria, Australia, 2007c. WorkSafe, Victoria, Prevention and management of aggression in health services: A handbook for workplaces, State Government Victoria, Melbourne, Victoria, Australia, 2008. WorkSafe, Victoria, Transferring people safely: A guide to handling patients, residents and clients in health, aged care, rehabilitation, and disability services, State Government Victoria, Melbourne, Victoria, Australia, 2009. WorkSafe, Victoria Ergonomics Unit, Officewise: A guide to health and safety, State Government Victoria, Melbourne, Victoria, Australia, 2006c. Young, K. and M. Regan, Use of manual speed alerting and cruise control devices by car drivers, Saf Sci, 45(4): 473–485 (2007). Zandvliet, D. and L. Straker, Physical and psychosocial aspects of the learning environment in information technology rich classrooms, Ergonomics, 9: 838–857 (2001). Zupanc, C. and R. Burgess-Limerick, Issues related to the wearing of fall-arrest harnesses in the construction industry, Ergon Aust, 17(3): 18–24 (2003). Zupanc, C. and R. Burgess-Limerick et al., Performance as a consequence of alternating controlresponse compatibility: Evidence from a coal mine shuttle car simulator, Hum Factors, 49: 628–636 (2007).

Chapter

45

Ergonomics in South Korea Soo-Jin Lee, Kyung-Suk Lee, Yong-Ku Kong, Myung-Chul Jung, and Kermit G. Davis CONTENTS 45.1 Introduction 45.2 Professional Development of Ergonomics of Korea 45.2.1 Ergonomics Society of Korea 45.2.2 Research Areas of the ESK 45.2.3 Research Activities of the ESK 45.2.4 Activities of Ergonomists 45.3 Typical Ergonomics Research Areas in Korea 45.3.1 Automobile Research 45.3.2 Cellular Phone Research 45.3.3 Agricultural Research 45.3.3.1 Aging Agricultural Community and Injuries from Agricultural Activities 45.3.3.2 Mid- to Long-Term Prevention Strategy for Agricultural Health and Safety 45.3.3.3 Research Achievements in Agricultural Safety and Health 45.3.3.4 Development of Protective Clothing for Workers in Cold and Hot Environments 45.3.3.5 Development of Educational Materials for Agricultural Work-Related Injuries 45.4 Management of Work-Related Musculoskeletal Disorders 45.4.1 WMSDs in Industrial Workers 45.4.2 WMSDs in Agricultural Workers 45.4.3 Korean Industrial Health and Safety Laws 45.5 Future Concerns References

1174 1174 1174 1174 1176 1176 1176 1176 1178 1179 1179 1180 1181 1184 1186 1187 1187 1188 1189 1191 1191

1173

1174    ◾    Occupational Ergonomics: Theory and Applications

45.1 INTRODUCTION The Korean economy was based on agriculture until the 1900s, when industrialization, especially in the areas of shipbuilding and steel and petrochemical production, began to play a larger role. Ergonomic improvements contributed to this process of economic development by maximizing work efficiency and productivity, improving the working environment, and advancing product safety and design. Ergonomic initiatives in Korea have concentrated on worker health and safety by focusing on work-related musculoskeletal disorders (WMSDs) and diseases that can result from workplace conditions. In Korea, ergonomic analysis began during the Korean War in the early 1950s, when the United States Air Force introduced ergonomic concepts through human research studies in aerial medicine [1]. In the 1970s, industrial ergonomics in Korea grew, particularly in the automobile and ship manufacturing sectors. This transformation continued in the 1980s, when computer- and office-based ergonomics became prevalent [1]. In the 1990s, WMSDs were finally recognized as medical disorders caused by occupational stress by the Workmen’s Accident Compensation Insurance Act [2]. A constructive revision of that act resulted in the Industrial Safety and Health Law of 2000, which requires employers to enact measures to prevent WMSDs [3]. The Industrial Safety and Health Law regulates that companies must take an active role in controlling WMSDs. Ergonomic improvements for farm workers also took place in the 1990s but were minor relative to the ergonomic advancements in other industries. In recent years, efforts to understand WMSDs have concentrated on identifying risk factors for WMSDs in agriculture.

45.2 PROFESSIONAL DEVELOPMENT OF ERGONOMICS OF KOREA 45.2.1 Ergonomics Society of Korea In 1982, the Ergonomics Society of Korea (ESK) was established by 40 founders, for “developing, spreading and applying ergonomics-related studies and technology for the profit of [the] general public [and] to contribute to advancement in ergonomics-related technology” [1]. By 1988, the society had expanded to 250 members and currently includes 591 members. Since 1982, the society has published the peer-reviewed Journal of the Ergonomics Society of Korea. Another major activity of the ESK is academic and research exchange during the ergonomics conference hosted every spring and fall. As a result of the expansion of ergonomics in Korea, 50 universities now have graduate programs in ergonomics or related fields, with approximately 550 graduates annually. 45.2.2 Research Areas of the ESK The ESK has not only increased its membership over time but has also experienced qualitative and quantitative growth in research publications, with several industrial sectors now recognizing the importance and service of ergonomics in workplaces and product design. Publication of Journal of the Ergonomics Society of Korea increased from twice a year from 1982 to 1996, to three times a year from 1997 to 2001, to four times a year from 2002 to the present, demonstrating the revitalization of ergonomics research. Table 45.1 shows that the number of published articles has risen every year, increasing 2.43-fold during the 1990s.

Ergonomics in South Korea    ◾    1175   TABLE 45.1  Number of Articles Focused on Ergonomics Published in the Journal of the Ergonomics Society of Korea Year

Vol. 1

Vol. 2

Vol. 3

Vol. 4

Total

Year

Vol. 1

Vol. 2

Vol. 3

Vol. 4

Total

1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995

4 2 3 4 5 5 6 4 5 4 11 6 6 10

4 2 2 4 6 4 4 5 8 6 6 6 8 9

— — — — — — — — — — — — — —

— — — — — — — — — — — — — —

8 4 5 8 11 9 10 9 13 10 17 12 14 19

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 Total

10 9 11 10 10 7 8 8 5 7 6 14 7

11 8 8 11 7 7 9 5 8 12 23 17 10

— 8 10 13 8 7 6 7 10 5 13 15 11

— — — — — — 10 6 6 11 17 20 13

21 25 29 34 25 21 33 26 29 35 59 66 41 593

The annual average was 19.4 articles in this period, compared to an average of 8.0 from 1982 to 1999. From 2000 to 2008, the society published 37.2 articles per year, for a 4.65-fold increase from the initial phase of the journal and an approximate two-fold increase from the middle phase of the society in the 1990s. Of the 593 articles published in Journal of the Ergonomics Society of Korea, most have concerned “physical ergonomics/WMSDs,” followed by articles on “product design/Kansei engineering,” including design of automobiles and cellular phones, “HCI/virtual environments,” and “cognitive engineering/human error” (Table 45.2). Other topics include anthropometry/standards, macroergonomics, environmental design, aging, and health care. Studies on physical ergonomics and WMSDs have consistently been published. Interestingly, more studies were conducted in the area of HCI than in product design in the 1980s. Nonetheless, more studies were published in the area of product design and Kansei engineering in the 1990s and 2000s than in the 1980s. TABLE 45.2  Percentage of Articles Published in the Journal of the Ergonomics Society of Korea for the Different Research Areas of Ergonomics Research Area Physical ergonomics/WMSDs Product design/Kansei engineering HCI/virtual environments Cognitive engineering/human error Anthropometry/standards Macroergonomics Environmental design Aging Health care Others

1980s

1990s

2000s

Mean

35.9 4.7 26.6 15.6 4.7 7.8 1.6 3.1 — —

28.9 20.6 16.0 14.4 6.7 2.1 4.6 2.6 3.1 1.0

28.7 23.9 11.9 13.7 6.9 5.1 3.3 3.3 1.8 1.5

29.5 20.7 14.8 14.2 6.6 4.4 3.5 3.0 2.0 1.2

1176    ◾    Occupational Ergonomics: Theory and Applications Research associates 6%

Professors 9% Public servants 10%

Other 11%

Large corporations 52%

Small and medium enterprises 12%

FIGURE 45.1  Distribution of ergonomic professionals in the Ergonomics Society of Korea.

45.2.3 Research Activities of the ESK One of major activities of the ESK is academic exchange, exemplified by the annual spring and fall ergonomics conferences. Since the fall conference of 1992, the ESK has established a topic for each conference. The number of articles published and presented at the conference has increased every year, for a total of 49 articles from 1982 to 1989 and 768 articles from 1990 to 1999, and an annual average of 76.8 articles, representing a 12.6-fold increase. In the 2000s, the society published a total of 1205 articles, for an annual average of 133.9, demonstrating significant growth since the initial and middle phases of the society. A total of 2022 articles have been presented at the conference as of the end of 2008. 45.2.4 Activities of Ergonomists Analysis of fields of activities for ESK ergonomics graduates from 50 universities with ergonomics or related programs shows that 281 of 545 total graduates entered large corporations and 27 went to small or medium enterprises, followed by 54 public servants, 51 professors, and 32 graduates working at national research institutes. Other graduates were involved in study-abroad programs, and 60 started new businesses. Figure 45.1 shows the distribution of ergonomics professionals in the ESK.

45.3 TYPICAL ERGONOMICS RESEARCH AREAS IN KOREA 45.3.1 Automobile Research The automobile is one of the most complex human–machine interface systems. Designing an automobile requires technology that must consider performance, function, and appearance. Automobiles have been transformed from a simple transportation vehicle to a driver’s living space, serving as mobile offices and entertainment centers. As a result, the current trend in automobile design applies not only to the automobile itself but also to the information systems and additional functional devices within the vehicle. The internal cab of the vehicle is a primary ergonomic focus area, specifically in the design of the seat, driving console, and accessory console with radio, heater, and air conditioner. The multiple themes that appear

Ergonomics in South Korea    ◾    1177  

in many automobile-related ergonomics case studies include Kansei engineering methods, subjective preferences with respect to ergonomic stress, and objective quantitative methods. Using Kansei engineering methods, Bahn et al. [4] developed complex models for automobile crash pads based on user perceptions. By manipulating the tactile and visible design characteristics of the crash pad, the Kansei engineering method was applied to incorporate luxuriousness. A similar Kansei engineering study developed perception models for the luxuriousness of interior materials [5]. Kansei engineering has also been applied to vehicledriving simulators. Chung et al. [6] examined perception vocabularies in evaluating the motor sensation of a vehicle-driving simulator. Choi et al. [7] determined the optimal position of the accelerator and brake pedals, leading to guidelines for accelerator and brake pedal positions, based on subjective lower body and extremity discomfort data for three different body sizes. Figure 45.2 shows the starting point and axle of the mock-up vehicle cab used in the research. Other studies in this area used a combination of subjective user satisfaction and objective experimental data. For example, one study examined driver satisfaction when entering and riding in a sport utility vehicle (Figure 45.3) and presented an ergonomic layout for the driver’s seat that maintained an optimal driving position, generated using a three-dimensional motion analysis system to analyze driver movement [8]. Lim and associates [9] investigated three control types and two display menus to find the best choices for driver performance and preference. To reduce fatigue in lower leg muscles during repeated pedal pressing when driving, Kim and Seo [10] relied on objectively measured data rather than subjective user  preference. They used electromyography (EMG) of the lower leg muscle to evaluate a heel rest during pedal activation. Park et al. [11] analyzed the relationship

Steering column axis

H-point (SAF)

Seat track

Z(+) X(+) Y(+)

Seat mounting point

FIGURE 45.2  An example of a mock-up of a vehicle cab that includes starting point and axle used

in ergonomic research.

1178    ◾    Occupational Ergonomics: Theory and Applications

FIGURE 45.3  Simulated motor cab utilized in the analysis of satisfaction when entering an

automobile.

between ­subjective body discomfort when seated and body pressure distribution of vehicle seats using a force-sensing resistor made of polymer. 45.3.2 Cellular Phone Research Research on cellular phones in Korea has concentrated on usability, including universal design, sensible design for high-end cellular phones, and input functions of Hangul (the Korean alphabet) characters. Each cellular phone manufacturer uses different Hangul input methods, leading to the need for standardization. Figure 45.4 shows the different Hangul input methods, each with 19 consonants and 21 vowels on 12 buttons. The first input method (far left) appears to be superior based on the result of experiments measuring variables including user input time, input error, and satisfaction [12,13]. Jun and associates [14] developed a structural equation model to examine the perceptual factors that influence user satisfaction while using a cellular phone. Kim and colleagues [15] suggested a multicentered usability method involving developers, evaluators, and users. The goal is to prevent the production of many variable end products, an outcome 1 |

2 .

3 —

1

2

3

1

2

3

1

2 |—

3

1

2

3

4

5

6

4

5

6

4

5

6

4

5

6

4

5

6

7

8

9

7

8

9

7

8

9 |

7

8

9

7

8

9 |—

*

0

#

* |

0 .

# —

*

0 –

#

*

0

#

*

0

#

FIGURE 45.4  Hangul input methods for cellular phones.

Ergonomics in South Korea    ◾    1179  

that occurs particularly when products are developed only by evaluators. Kim et al. [16] compared three approaches—quantification, neural network, and decision tree—for analyzing perceptions about cellular phone design. The strengths and weaknesses of each modeling method were discussed using a specific cellular phone example. The concept of a universal design for cellular phones has particular ramifications for the elderly and people with disabilities. Hong [13] emphasized the need for less retentive functions and the use of simple keys when designing a cellular phone for the elderly. Kim et al. [17] developed a universal design index applicable to cellular phone evaluation. 45.3.3 Agricultural Research Since the 1960s, policies that focus on increased food production have led to innovations in agricultural technologies and formed the basis of the green and white revolutions. However, these policies threatened the health of agricultural workers by leading to increases in the prevalence of WMSDs and increasing the number of safety concerns due to the use of agricultural machinery and agrichemicals. Among the key WMSD issues in farming are the high percentages of aging and female farmers [18]. The Korean government recently developed policies that protect agricultural workers while focusing on increasing agricultural production, balancing the need for worker health and safety, with meeting the demands for food in Korea. One specific initiative was the national action plans established in 2005 to promote the improvement and maintenance of the health of agricultural workers and fishermen. These action plans enabled the government to conduct specialized research programs to investigate the conditions under which accidents and injuries occurred during farm work, and provided an opportunity for the government to prioritize resources to address health outcomes [19]. 45.3.3.1  Aging Agricultural Community and Injuries from Agricultural Activities Rapid industrialization and economic development in Korea has significantly reduced the farming population. In 1945, 87% of the Korean population was in the agricultural sector, but by 2007, only 6.8% of the population made a living in agriculture. One of the major outcomes of this major shift in the farming workforce was the concentration of older individuals into a significant proportion of the agricultural workforce, of which 42% were 60 years of age and older [20]. This makes Korean agriculture one of the oldest working industry sectors in the developed world. As a result of the workforce becoming older, degenerative and chronic diseases are on the rise among famers and pose a significant burden on these farmers and on Korean society. Lee [19] at the Rural Development Administration (RDA) reported prevalence rates of chronic diseases related to “farmer disease” as between 20% and 45%, as reported every 5 years since 1995. Many underlying conditions place these older farmers at increased risk for cumulative disorders and WMSDs, including high blood pressure, rheumatism, arteriosclerosis, and kidney disease. The RDA has conducted studies on WMSD risk factors, nerve injuries from agrichemical poisoning, asthma, and immune deficiency since 2000 [21–23,25]. WMSDs vary among agricultural workers, depending on the type of work performed, the type of crop, and

1180    ◾    Occupational Ergonomics: Theory and Applications TABLE 45.3  Surveys on WMSDs for Agricultural Workers Relative to Traditional Non-Agricultural Workers Surveya

Year

No. of People

RDA [21]

2007

416

RDA [22]

1999

1700

RDA [23]

2001

354

Paek [24]

1999

1709

Prevalence Rate

Remarks

Agricultural workers 75%

Medical examination, relation to agricultural work (41%) National health and nutrition data at or above the age of 30

Agricultural workers/fishermen 62% Nonagricultural workers 25% Orchard 67% Agriproducts 60% Livestock farming 35% Nonagricultural workers 31% Agricultural workers/fishermen 82%

Medical examination, complete inventory as a function village unit Questionnaires for all males between the ages of 45 and 64

Manufacturers 71% a

RDA: Rural development administration.

whether livestock are involved (Table 45.3). Based on these studies, the predominant conclusion is that the prevalence of WMSDs in the agricultural sector is significantly higher than in the general public and nonagricultural workers (Table 45.3). In 2001, chronic diseases occurred in farmers 1.45 times more often than in nonagricultural general population workers, and WMSDs occurred 2.4 times more frequently [19]. According to workers’ compensation data from the Ministry of Labor, farming had a higher injury rate than either the manufacturing or construction industries (Table 45.4) [25]. Specifically, the accident rate is a dangerous 34.7 per 1,000 workers from agricultural activities, as determined from compensation data from safety aid systems, which includes approximately 700,000 agricultural workers (Table 45.5) [26]. 45.3.3.2  Mid- to Long-Term Prevention Strategy for Agricultural Health and Safety As indicated earlier, an aging workforce is a concern of the agricultural industry, but it is not the only health and safety issue for the agricultural community. A specialized TABLE 45.4  Injuries by Industrial Classification in the Workers’ Compensation Data from the Ministry of Labor in 2006 [20] Type of Industry

No. of Workplaces

No. of Laborers

Industrial Disaster Victims

Injury Rate per 1000 People

3,281 236,429 149,874

31,781 3,032,667 2,547,754

483 35,914 17,955

15.20 11.84 7.05

Farming Manufacturing Construction

TABLE 45.5  Injuries in Safety Aid System of Agricultural Workers and Mutual Aid System of Agricultural Machines in 2005 [24] Safety Aid System of Agricultural Workers

Mutual Aid System of Agricultural Machines

No. of Subscribers 702,000

No. of Accidents

Rate per 1000 People

No. of Subscribers

No. of Loss of Farm Machines

Rate per 1000 People

13,930

34.7

8,742

731

83.6

Ergonomics in South Korea    ◾    1181   TABLE 45.6  Mid to Long-Term Research Plan on the Safety and Health for Agricultural Work in the Rural Development Administration Component Ergonomic work improvement technology development by agricultural process

Investigation of the causes of agricultural work-related injuries

Research on management of exposure to primary risk factors in the agricultural working environment

Research on implementation of a system tracking compensation of agricultural injuries

Contents • Research on working environment improvements that reduce worker burden of labor • Development of work management guidelines • Development of equipment and interventions to protect agricultural workers • Development of ergonomic agricultural injury tracking system • Research on the status of agricultural injuries • Research to evaluate the influence of agricultural work risk factors on worker health • Monitoring agricultural injury prevalence and development of management systems • Implementation of a national statistical system for agricultural injuries • Investigating the prevalence and exposure to biological risk factors from agricultural livestock work • Analysis of risk of exposing agricultural risk factors by agricultural species • Establishing risk exposure level (REL) by risk factors • Implementation of a prevention and management system for agricultural injuries • Development of agricultural health and safety educational programs • Development of regulations for agricultural worker injury compensation and development of a tracking system for compensated injuries

system that identifies and tracks agricultural activities that create risks for farm workers, and determines the level of compensation for injuries is needed. Since researchers actively adopt strategies to understand the types and causes of injuries, the relevant research institutes and RDA specialists are conducting mid- to long-term studies in cooperation with academic institutions to examine the status of agricultural worker injuries and association with the type of work performed. They are also developing improvement strategies for farm working environments [27]. Table 45.6 provides a detailed outline of the plan that is currently being implemented [27]. 45.3.3.3  Research Achievements in Agricultural Safety and Health 45.3.3.3.1  Developing Equipment to Improve Agricultural Working Postures  To control farm work-related injuries, several interventions have been developed and implemented to improve agricultural working environments. Some general examples are equipment and devices to eliminate the carrying of unusually shaped or heavy loads, and protection guards on machinery. Many farm tasks require awkward postures that place stress on the

1182    ◾    Occupational Ergonomics: Theory and Applications TABLE 45.7  Assistive Technology for Improving Working Posture Working Posture Bending [30] Squatting [31,32]

Sitting on the ground [30]

Crop Type

Type of Work

Improvement

Grapes Outdoor peppers Strawberries under structure Cultivation under structure Agarics Strawberries Cucumbers

Berry thinning Harvesting Growing seedling, hydroponic, harvesting Management, harvesting

Slope-regulated cycle work chairs Small and large platform carriers Cultivation vehicle at the height of cultivated crops Put-on chairs

Grading, shipping Grading, shipping Grading, shipping

Grading and packaging bench Strawberry grading bench Shipping work of cucumbers

shoulders or back and result in fatigue and WMSDs [28]. Recent initiatives in farm mechanization have reduced much of the manual lifting, but awkward body posture, including bending of the back, squatting of the legs, or pulling back of the head, can lead to degeneration of the musculoskeletal system [29]. Researchers have developed various devices to improve working postures (Table 45.7), and some equipment is produced as part of government support programs to improve agricultural working environments. The RDA has conducted several demonstration projects for interventions and devices that reduce poor posture when performing agricultural work, including strawberry-harvesting vehicles, slope-regulated cycle work chairs, platform work chairs, and benches for grading and shipping mushrooms (Figure 45.5). 45.3.3.3.2  Reducing Heavy Loads in Farm Work  Handling heavy loads in agricultural activities includes not only lifting, moving, and lowering but also pushing and pulling. Many agricultural tasks require long periods of carrying, moving, or lifting, sometimes with irregularly shaped loads. Loads carried include fertilizer for harvesting and regulating crops, heat insulators, and crops transferred into different harvesting containers. Recently, platform carriers that adapt to loads of various shapes have been developed and used to transport harvested crops [30]. However, more studies are needed to ensure safety when transporting heavy loads, especially for older and female workers. When possible,

(a)

(b)

(c)

(d)

FIGURE 45.5  Assistive technology for removing awkward working posture: (a) strawberry grad-

ing bench, (b) slope regulated cycle work chairs, (c) platform work chair, and (d) grading and shipping bench.

Ergonomics in South Korea    ◾    1183  

handles should be included on all objects being lifted or carried. Jung et al. [28] report that the maximum weight allowance of a box without handles is 7.2%–16% lower than that for a box with handles. Another study determined that container handles improve work efficiency and comfort level [33]. Interventions have been developed to assist in the transport of harvested peppers, cucumbers, strawberries, tomatoes, Chinese matrimony vines, fruit trees, squashes, chrysanthemums, mushrooms, and roses (Figure 45.6). In addition, a multipurpose vehicle has been developed to move seedling cases. Studies of platform carriers that evaluate work efficiency and comfort level by physiological, biomechanical, and subjective evaluation are in Table 45.8. The agricultural work environment is designed for crops rather than workers. For example, the ridges along which crops are grown are awkward to walk on, and greenhouse aisles are often too narrow. In addition, fields become muddy and uneven over the planting and growing seasons, resulting in increased muscular demand and potential fatigue. Circumstances are even more burdensome when farm workers are required to step over fruit and vegetables on the ground such as watermelons, yellow melons, strawberries, and lettuce. To avoid crops, the farm worker may adopt unsafe postures that require sudden loading, an unstable gait, or unsafe posture. Another task that may induce WMSDs is extended reaching. Pruning and harvesting of apples, pears, and grapes, where workers

(a)

(b)

(c)

(d)

FIGURE 45.6  Assistive technology for transporting agricultural product: (a) platform carrier for

outdoor peppers, (b) platform carrier for strawberries, (c) platform carrier for fruit vegetables, and (d) rail platform carrier. TABLE 45.8  Assistive Technology for Transporting Agricultural Products Crops Watermelons, lettuce, scallions [34,35] Cucumbers, tomatoes [30] Strawberries [30] Yellow melons, strawberries, melons [36] Greenhouse cultures [37] Outdoor peppers [30] Scallions [35]

Carriers

Evaluation Methods

Chairs with wheels, carriers

Physiological reaction, etc.

Human power and power-driven harvest platform carriers Platform carriers for strawberries Rail platform carriers

Energy consumption, work efficiency

Handy autonomous vehicles for greenhouse Small and large platform carriers Chairs with wheels, handcarts

Energy consumption, work efficiency Biomechanical evaluation, work efficiency Performance Energy consumption, work efficiency Physiological reaction, subjective symptoms

1184    ◾    Occupational Ergonomics: Theory and Applications TABLE 45.9  Assistive Technology for Working Condition Risk Factors Ground conditions [34]

Characteristics

Working area [38]

Improving and evaluating uneven and slanted ground Ridges, furrows

Height of bed culture [31]

Improving bed culture of strawberries

Improvement

Evaluation Methods

Flat ground

Heart rate, fatigue

Appropriate widths of ridges and furrows Elevated bed culture

Principles of motion economy Work hours, postures, and yields

have trouble reaching the fruit, may produce excessive force on the lower back, shoulders, and upper extremities. Finally, poor posture may result from cleaning and sorting crops where a squatting position is usually adopted, which may place extreme stress on the lower extremities and lower back. To improve such work, Yoon et al. [31] raised the bed culture of strawberries to waist level, which improved working posture, decreasing the risk of WMSDs and increasing work efficiency (Table 45.9). 45.3.3.4  Development of Protective Clothing for Workers in Cold and Hot Environments Agricultural workers are frequently exposed to extreme cold or hot temperatures. Since most work is outdoors, exposed to the elements, the primary environmental worry in the summer is heat exhaustion or, more seriously, heat stroke. In winter, the main issue is frostbite [29]. In extremely cold weather, loss of life can result from prolonged temperature loss. To combat extreme environmental temperatures, farmers often wear protective clothing to reduce the physiological burden. The RDA has developed and supplied various protective TABLE 45.10  Assistive Technology for Agricultural Working Cloth Risk Factors Ultraviolet rays [39] High temperature [40] High temperature [41] Cold weather [42]

Characteristics Blocking ultraviolet rays, thermal comfort Removability, cooling time, reduction in weight —

Ultraviolet rays, solar radiation [45,46]

Waterproof, cold protection Convenience, functional improvement Materials, shapes and height of heels Waterproof coating, ventilation, wearability Blocking sunlight, ventilation, portability

Exposure to agrichemicals, heat [47,48]

Waterproof, water permeability, water repellent

Discomfort in body movement [43] Heat stress [44] Heat stress [30]

Improvement Working clothing for a greenhouse Cooling vest Working clothing for outdoor peppers Working clothing for dropwort Working clothing for fruit trees (pears) Work shoes on a field Sprout and bud-picking gloves Blocking sunlight, functionality Enhanced material protecting clothing from agrichemicals

Evaluation Methods Physiological reaction, subjective sensation Physiological reaction, subjective sensation Ergonomic workload test Physiological reaction, subjective sensation Field test, functional test Physiological reaction, subjective sensation Satisfaction, subjective sensation Subjective sensation, human physiological experiment Physiological burden, subjective sensation, efficiency of materials

Ergonomics in South Korea    ◾    1185  

clothing for working in greenhouses, interacting with livestock, handling agrichemicals, and providing protection from water and cold during the rainy season (Table 45.10 and Figure 45.7). Additional examples of protective clothing for farmers are specially designed fatigue-resistant work shoes for field work and antifatigue gloves for picking and pruning the sprouts and buds of fruit vegetables. Advanced virtual human modeling has been used to determine the best method for completing specific farm tasks or using certain types of equipment (Figure 45.8) [36]. The premise is that problems in farming components can be improved and demonstrated through virtual human modeling, saving significant expense and time. In an industry with limited resources, these are always major concerns in developing new interventions. The RDA also recently applied anthropometric principles to investigate unique characteristics of individuals and their relationship to farm work performance [49,50]. In anthropometric measurements of 2000 Korean agricultural workers, a high prevalence of “bow-shaped” legs was found in female agricultural workers (Figure 45.9) [49] and found to be related to a squatting working posture [49]. The RDA also reported that the waist size of rural women of all ages tended to be larger than those of urban women [50]. These data must be considered

(a)

(b)

(c)

(d)

FIGURE 45.7  Assistive technology of protective clothing equipment: (a) agricultural work shoes,

(b) sprout and bud picking glove, (c) heat protective hat, and (d) sun-blocking cart.

y z x

z

y

x

FIGURE 45.8  Evaluation of farmer while moving farm equipment using a human model.

1186    ◾    Occupational Ergonomics: Theory and Applications

FIGURE 45.9  Anthropometric measurement of a agricultural worker.

when developing interventions and programs for agricultural workers since not all workers will be a standardized size. Equipment, machinery, clothing, and tools will not necessarily be one size fits all and will need to be adjusted for different working populations. 45.3.3.5  Development of Educational Materials for Agricultural Work-Related Injuries Starting with an agricultural worker health management class model in 1995, the Korea Information Center of Agricultural Safety and Health developed educational programs for agricultural worker health and safety, including an exercise program to reduce worker fatigue (1997), an occupational disease-related risk factor management system (2000), and implementation of programs for the prevention and management of agricultural injuries (2006). Furthermore, the center provides summaries of the programs to the workers and the general public as handbooks (Figure 45.10) and through an online service (Figure 45.11).

FIGURE 45.10  Agricultural safety and management handbooks.

Ergonomics in South Korea    ◾    1187  

FIGURE 45.11  Korea Information Center of Agricultural Safety and Health (http://farmer.rda.go.kr).

45.4 MANAGEMENT OF WORK-RELATED MUSCULOSKELETAL DISORDERS 45.4.1 WMSDs in Industrial Workers The first case of compensation for an occupational disease in Korea occurred in 1986, involving a broadcasting station typist. This served as a starting point for injury management, recording, and compensation for laborers [51]. Since 1980, the Ministry of Labor has announced the official status of occupational diseases each year in accordance with the Industrial Accident Compensation Law. According to these data, no cases of WMSDs from cumulative trauma were reported until 1992. In 1993, two cases were reported (Table 45.11). These cases increased the interest of labor unions, progressive nongovernment organizations, and industrial public health experts. Since then, the number of reported WMSD cases increased rapidly until 1997. In that year, the foreign currency crisis stagnated the Korean economy, with many companies laying off massive numbers of workers. As a result, laborers emphasized survival at their workplaces, giving priority to work over compensation for occupational injuries, and the number of WMSD cases decreased. During the economic recovery, work intensity increased because of sustained productivity with a smaller workforce, leading to working environment that was more prone to WMSDs. TABLE 45.11  Workplace Musculoskeletal Disorder (MSDs) Cases in South Korea (The Ministry of Labor, Labor Statistics 2008) Occupational Disease Year

No. of Total Workers

No. of Total Diseases

No. of WMSDs (%)

1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 Total

7,582,479 7,441,160 9,485,557 10,581,186 10,571,279 10,599,345 10,473,090 11,059,193 11,688,797 12,528,879 102,010,965

1,838 2,732 4,051 5,653 5,417 9,130 9,183 7,495 10,235 11,472 67,206

124(6.7) 344(12.6) 1,009(24.9) 1,634(28.9) 1,827(33.7) 4,532(49.6) 4,112(44.8) 2,901(38.7) 6,233(60.9) 7,723(67.3) 30,739(45.7)

1188    ◾    Occupational Ergonomics: Theory and Applications

In 1998–1999, 200–300 cases of WMSDs were reported each year, including an increase from 1000 to 2000 from 2000 to 2003 and a further rise after 2003–2004, with approximately 4000 reported cases [52]. By 2007, 7723 people reported a WMSD, which accounted for 62.7% of the total number of laborers with an occupational disease [52]. The number of WMSD cases in 2007 was 166% of the 2005 number. One potential contribution to this sudden increase was a change in the reporting of low back pain (Table 45.11) [52]. Of all the WMSDs, 75% occurred in the manufacturing industry, specifically the automobile and shipbuilding industries [53]. Recently, more cases of WMSDs are being reported in other industries such as the restaurant, lodging, health, social welfare, banking, and insurance industries [53]. The average compensation cost per WMSD case is estimated to be $35,000–$45,000 [54]. The rapid increase in WMSDs not only threatens worker health and welfare but also imposes a heavy financial burden on the Korean economy as a whole. 45.4.2 WMSDs in Agricultural Workers Korean farms are typically characterized as small-scale independent farms, often run by a family unit [55]. Even with an increase in mechanized farming equipment, many agricultural activities remain heavily dependent on human labor [55], so agricultural workers are exposed to long work hours and ergonomic risk factors for WMSDs. While WMSDs are one of the most serious problems threatening agricultural worker health and welfare in Korea, researchers have only recently conducted systematic studies on work-related WMSDs. In 1233 agricultural workers examined by the RDA in 2006, prevalence rate for WMSD symptoms in the previous 12 months that lasted at  least 1 week or occurred at least once a month was 81%. Prevalence rates by body part were 52% in the back, 51% in the legs/knees, and 38% in the shoulders [56]. In addition, 416 Korean agricultural workers were randomly selected and examined by physicians and radiological tests, including x-ray, CT, and MRI, revealing a WMSD prevalence rate of 75%. Injury types for the agricultural workers were 94 cases of “osteoarthritis of the knee,” followed by 65 cases of “non-specific chronic back pain,” 62 cases of “myofascial pain syndrome,” and 49 cases of “radiculopathy of the back” [21]. Based on the collected data, farm work significantly contributed to the physical conditions in approximately 41% of the diseases [21]. Korean agricultural workers are exposed to different WMSD risk factors than laborers in the general manufacturing industries, and the risks are dependent upon the crop produced and livestock raised [57–59]. Pomiculture workers frequently report WMSDs of the neck, shoulders, arms, and elbows due to repetitive work with the neck flexed or bent backward or working with their arms above their shoulders [57,58]. Another example of crop-specific WMSDs is seen in greenhouse workers, or workers who harvest peppers, strawberries, yellow melons, and watermelons. This work, which occurs below knee level [58–60], requires the worker to bend forward significantly or sit in a squatting posture, potentially resulting in hip and knee WMSDs [58–60]. Lee and associates [21] examined ergonomic risk factors and WMSD symptoms in agricultural workers, finding higher prevalence rates of 45% in the hips and waist and 42%

Ergonomics in South Korea    ◾    1189  

in the lower bodies than in other parts of the body. Various postures were observed in agricultural workers, including a squatting posture, a bending posture in which workers bent their knees 30°–120°, and sitting cross-legged [21]. These postures may cause changes in body shapes [50,58]. Moreover, some have pointed out that such working postures may have led to frequent cases of “osteoarthritis of the knee” and “bow leg” [56,59]. The rapid entire body assessment (REBA) and Ovako working posture assessment system (OWAS) are frequently used as ergonomic assessment tools in agricultural work [61]. However, they oversimplify postures for the legs and knees or do not reflect the frequent working postures used in Korean agricultural work and thereby underestimate the WMSD risk for these body parts [61]. Based on this research, the RDA and other researchers [62] compared physiological burdens (e.g., heart rate), muscle activation levels (via EMG), and subjective discomfort rating in various lower body postures to develop a Korean ergonomic assessment tool specialized for leg and knee risk factors. 45.4.3 Korean Industrial Health and Safety Laws In Korea, the enforcement regulation (Number 2, Paragraph 1, Article 16) in the Industrial Accident Compensation Law first recognized “cervicobrachial syndrome” as a type of occupational disease in 1994. In the late 1990s, the Korean government established “Work Management Guidelines [for] Laborers Handling Visual Display Terminals” (“VDT” hereafter; Ministry of Labor Announcement No. 1997-8), “Work Management Guidelines [for] Laborers Performing Simple Repetitive Work” (Ministry of Labor Announcement No. 1998-15), and “Work Management Guidelines [for] Prevention Of Occupational Lumbago” (Korea Occupational Safety and Health Agency (KOSHA) CODE H-05-1998) to initiate work environment management and prevention of WMSDs [2]. All regulations aimed to document and control WMSDs in the workplace. In the last decade, WMSDs have become a major issue in Korean industrial settings, leading to the conclusion that previous government recommendations have not been effective in preventing WMSDs. As a result, the government revised the Industrial Safety and Health Law in 2003 and established employer obligations to prevent WMSDs. Based on this new regulation, Korean companies improved work environments and the employee health and safety budgets [63,64]. Large corporations hired WMSD experts or fostered in-house experts to investigate and improve risk factors in the workplace. However, many small businesses cannot carry out WMSD prevention and management measures at the level required by the revised law because of budgetary concerns. The government has begun to enforce regulations for the most strenuous workplaces and jobs. Detailed management of the risk factors is regulated so that employers are required to provide notification of risk, provide education to employees, implement a medical management and prevention program, and reduce employee exposure to heavy load tasks. In this new regulation, the government suggested 11 items that should be considered strenuous and risky for WMSDs. The regulation was similar in content to the Washington State Ergonomic Rules—WAC-296-62-05174, Caution Zone Job—in the United States, which is used to define ergonomic requirements for risk factor investigations and working

1190    ◾    Occupational Ergonomics: Theory and Applications

environment improvements [3]. The following is a list of the 11 key items that must be controlled to reduce WMSDs in the workplace: 1. Performing intensive tasks using a keyboard or mouse for more than 4 h total per day 2. Repeating the same motion with the neck, shoulders, elbows, wrists, or hands (excluding keying activities) more than 2 h total per day 3. Working with the hand(s) above the head, the elbow(s) above the shoulders, or the elbow(s) far away from or behind the body more than 2 h total per day 4. Working with the neck or the back bent or twisted without support and without the ability to vary posture more than 2 h total per day 5. Squatting or kneeling more than 2 h total per day 6. Pinching an unsupported object(s) weighing 1 or more kg per hand, or pinching with a force of 2 or more kg per hand, more than 2 h total per day

7. Gripping an unsupported objects(s) weighing 4.5 or more kg per hand, or gripping with a force of 4.5 or more kg per hand, more than 2 h total per day

8. Lifting objects weighing more than 25 kg more than 10 times per day 9. Lifting objects weighing more than 10 kg above the shoulders, below the knees, or at arm’s length more than 25 times per day 10. Lifting objects weighing more than 4.5 kg if done more than twice per minute, more than 2 h total per day 11. Using the hand (heel/base of palm) or knee as a hammer more than 10 times per hour, more than 2 h total per day Employers must perform risk factor investigations, covering facility and production line conditions, workload, task speed, cycle time, working posture, work method, and symptoms and signs of WMSDs in employees. A risk factor investigation must be conducted once every 3 years or once a WMSD is reported, when new jobs and equipment are introduced or when workload and working environment are modified. The law also states that representatives of the workers must participate in the investigation procedure. Furthermore, employers are obligated to conduct a WMSD prevention program when 10 or more employees suffer from WMSDs, or 5 or more employees suffer from WMSDs, if that is equal to or greater than 10% of the total number of employees. The law defines specific guidelines for manual material handling jobs. It recommends limiting weight and considering the frequency, transfer distance and speed, and work/rest ratio in lifting tasks. The regulation also recommends that employers notify the employee of the exact weight of the material and the proper handling method for objects weighing more than 5 kg.

Ergonomics in South Korea    ◾    1191  

45.5 FUTURE CONCERNS The biggest problem facing the industrial health and safety system in Korea is that small business laborers and independent agricultural workers are extremely vulnerable to industrial injuries and occupational diseases. Since the Industrial Safety and Health Law applies only to workplaces with five or more employees, about 99% of small business workers and most agricultural workers on family-run farms are not covered. As a result, these workers do not benefit from many of the regulations on work environment management, surveillance of occupational diseases, or compensation and rehabilitation for industrial injuries. Overall improvement to these small businesses needs to be a high priority in the near future. For a sustainable Korean agriculture, workers and their family members must be supported in adopting safe and healthy practices for performing farm work. Korea should reinforce research projects and education programs to prevent injuries on the job. Korea should also establish a compensation system to protect agricultural workers and their family members as well as to expand the social safety net, so quality of life is maintained after an injury has occurred.

REFERENCES 1. N. S. Lee, C. M. Lee, K. Nah, B. Park, D. H. Lee, K. S. Kwon, D. C. Lee, S. J. Park, and H. S. Park, 20 Year’s history of the ergonomics society of Korea, J. Ergon. Soc. Korea 22(2):69–92 (2003). 2. S. J. Lee and Y. S. Kim, Current trends of work-related musculoskeletal disorders (WMSDs), Hanyang J. Med. 19(2):31–39 (1999). 3. Korean Occupational Safety and Health Agency, Regulation and technical guideline for prevention for WMSDs, Incheon, Republic of Korea, 2003. 4. S. W. Bahn, C. Lee, J. H. Lee, and M. H. Yun, Development of luxuriousness models for automobile crash pad based on subjective and objective material characteristics, J. Ergon. Soc. Korea 25(2):187–195 (2006). 5. H. C. You, T. B. Ryu, K. H. Oh, M. H. Yun, and K. J. Kim, Development of satisfaction models for passenger car interior materials considering statistical, technical, and practical aspects of design variables, IE Interfaces 17(4):482–489 (2004). 6. Y. H. Chung, S. S. Eom, K. Sohn, and K. H. Choi, A human sensibility ergonomics method for vehicle driving simulator and verbal expressions collected, J. Ergon. Soc. Korea 19(2):1–14 (2000). 7. J. P. Choi, E. S. Jung, S. J. Park, and S. W. Jeong, Optimal layout of vehicle pedals depending on the types and positions of vehicle pedals, J. Ergon. Soc. Korea 26(4):91–100 (2007). 8. S. J. Park, Y. K. Yim, H. J. Lee, and C. J. Kim, The study on the satisfaction and a motion analysis when entering a car through change of vehicle conditions, J. Ergon. Soc. Korea 25(3):25–32 (2006). 9. H. U. Lim, E. S. Jung, S. J. Park, and S. W. Jeong, Comparisons of driver performance with control types of the driver information system, J. Ergon. Soc. Korea 26(1):1–100 (2007). 10. J. Y. Kim and K. B. Seo, The effect of the heel rest on the lower leg muscle activity and fatigue during repetitive pedaling, J. Ergon. Soc. Korea 24(4):55–62 (2005). 11. S. J. Park, N. S. Lee, and S. Lee, An investigation of the relationship between subjective comfort evaluation and body pressure distribution of vehicle seats, J. Ergon. Soc. Korea 12(1):3–15 (1993). 12. D. Kee, Evaluation for performance and preference of Hangul entry methods using real mobile phones, J. Ergon. Soc. Korea 25(3):33–41 (2006).

1192    ◾    Occupational Ergonomics: Theory and Applications 13. S. K. Hong, Universal design of Hangul input method for mobile phones, J. Ergon. Soc. Korea 26(3):117–124 (2007). 14. Y. H. Jun, I. K. Baek, J. I. Kim, and K. H. Son, A study on causal relationships among sensibility satisfaction factors for mobile phone, J. Ergon. Soc. Korea 22(2):1–13 (2003). 15. J. Y. Kim, H. Y. Lee, and Y. C. Choi, The structuring process of multi-centered usability evaluation method, J. Ergon. Soc. Korea 24(2):25–33 (2005). 16. I. K. Kim, C. Lee, and M. H. Yun, A comparison of modeling methods for a luxuriousness model of mobile phones, J. Ergon. Soc. Korea 25(2):161–171 (2006). 17. M. Y. Kim, S. Park, and E. S. Jung, Development process of a universal design evaluation index with a case study for mobile phone evaluation, J. Ergon. Soc. Korea 25(4):51–62 (2006). 18. K. R. Kim, A study on the farmers’ health status and musculoskeletal workload, PhD thesis, Seoul National University, Seoul, Korea, 2008. 19. K. S. Lee, A study on the management system for occupational disease and injury of farmers, PhD thesis, Seoul National University, Seoul, Korea, 2006. 20. Korea National Statistical Office, Basic agricultural statistics survey, 2008. 21. Rural Development Administration, Development of the standardized diagnostic tool for farmer’s work-related musculo-skeletal disorders and evaluation of the work-relatedness of musculo-skeletal disorders, 2009. 22. RDA, Report on comparison and analysis for main disease and health status in farmer and fisherman, National Academy of Agricultural Science, Suwon, Republic of Korea, 2004. 23. RDA, Hazard assessment for risk factors in farmer work-related disease and development of total management system, 2002. 24. D. M. Paek, In-depth and link analysis—The annual report of the National Health and Nutrition Survey in 1998, 1999. 25. Ministry of Labor, 2006 Annual report of work injury insurance, 2007. 26. Ministry of Agriculture, A study on patterns and characteristics of agriculture-related injury by analysis of safety aid system of farm workers, 2007. 27. Rural Development Administration, Mid-term and long-term plan for prevention strategy of agricultural accidents and management of farmer’s health, 2007. 28. K. G. Davis and S. E. Kotowski, Understanding the ergonomic risk for musculoskeletal disorders in the United States agricultural sector, Am. J. Ind. Med. 50(7):501–511 (2007). 29. D. S. Lim, H. C. Kim, H. S. Chae, K. R. Kim, S. J. Lee, and K. S. Lee, A study on agricultural safety technology for ergonomic intervention in farm-work, J. Ergon. Soc. Korea 29(2):225–239, 2010. 30. Rural Development Administration, A handbook of the assistive technology for enhancement of farm-work: Tools and personal protective equipments, 2008. 31. H. S. Yoon, Y. H. Hwang, C. K. An, H. J. Hwang, and C. W. Rho, Growth and fruit yield of strawberry grown in raised bed culture using growing media with lower cost, Kor. J. Hort. Sci. Technol. 22(3):266–269 (2004). 32. H. S. Jung and H. S. Jung, Evaluation of proper height for squatting stool and the ergonomic design of wearable stool, IE Interface 18(3):288–296 (2005). 33. H. S. Jung, A. S. Park, and H. S. Jung, Ergonomic design and evaluation of carrying handles for bag, IE Interface 17(1):46–55 (2004). 34. M. J. Kim and J. W. Choi, A Study for farmers to reduce workload on the different working conditions (part 1)—Cultivating lettuce in the winter greenhouse, Korean J. Commun. Living Sci. 8(2):111–117 (1997). 35. M. J. Kim and J. W. Choi, A study for farmers to reduce workload on the different working conditions (part 2)—Cultivating welsh onion in the summer ground, Korean J. Commun. Living Sci. 8(2):119–124 (1997). 36. Rural Development Administration, Development of an electronic vehicle for chamwoae of protected cultivation using agricultural ergonomics, No.11-1390000-002058-01 (2008).

Ergonomics in South Korea    ◾    1193   37. J. H. Lee and K. H. Ryu, Development of a simple autonomous vehicle for greenhouse works, J. Korean Soc. Agric. Machinery 21(4):422–428 (1996). 38. Rural Development Administration, Safety management booklets for elderly farmer (2006). 39. J. W. Choi and K. S. Hwang, Study in the effect of a cooling vest under hot environment, J. Korean Soc. Cloth. Text. 25(1):83–90 (2001). 40. J. W. Choi, M. J. Kim, and J. Y. Lee, Efficacy of cooling vests for alleviating heat strain of farm workers in summer, J. Korean Soc. Cloth. Text. 29(8):1176–1187 (2005). 41. J. W. Choi, M. J. Kim, and J. Y. Lee, Ergonomic investigation of the workload of red pepper harvest workers in summer: A pilot study for developing personal protective clothing, J. Korean. Soc. Living. Environ. Sys 14(1):9–19 (2007). 42. J. W. Choi and Y. J. Baek, Development the protective clothing for dropwort cropping workers, J. Korean Soc. Cloth. Text. 24(8):1266–1275 (2000). 43. M. S. Choi and S. P. Ashdown, The design and testing of work clothing for female pear farmers, Cloth. Text. Res. J. 20(4):253–263 (2002). 44. K. S. Lee and J. W. Choi, A study of agricultural fatigue shoes, Korean J. Commun. Living Sci. 7(2):99–108 (1996). 45. G. S. Kim and J. H. Choe, Development of movable sunshade tent, J. Korean Home Econ. Assoc. 42:1–15 (2004). 46. M. J. Kim and J. W. Choi, Thermal and subjective responses by sun hats for farmer in a hot climatic chamber, J. Korean Soc. Cloth. Text. 28:713–722 (2004). 47. J. W. Choi, M. J. Kim, and J. Y. Lee, Evaluation of the farmer’s workload and thermal environments during cucumber harvest in the greenhouse, Korean J. Commun. Living Sci. 9(3):245– 253 (2002). 48. K. S. Hwang, K. R. Kim, K. S. Lee, H. C. Kim, K. S. Kim, and Y. J. Baek, The textiles and the performance level in developing the pesticide proof clothing, J. Korean Soc. Cloth. Text. 31(11):1611–1620 (2007). 49. Y. J. Baek and K. S. Lee, Characteristics of the body shape of Korean woman farmers by crops, J. Korean Soc. Cloth. Text. 32(11):1584–1594 (2008). 50. Y. J. Baek, K. S. Lee, K. S. Hwang, K. R. Kim, and H. C. Kim, Characteristics of the somatotypes of Korean farmer, J. Korean Soc. Cloth. Text. 32(3):431–442 (2008). 51. B. K. Kim and J. Y. Kim, Current status of work-related musculoskeletal disorders in Korea, Proc. 30th Conf. Korean Occupational and Environmental Medicine, Seoul, Korea, pp. 7–12 (2003). 52. Ministry of Labor, Labor Statistics, 2008. 53. B. Y. Kwon, K. H. Park, Y. Kim, Y. M. Kim, and H. K. Choi, Analysis of incidence trend of workrelated musculoskeletal disorders (1998–2007) in Korea, Proc. Spring Conf. the Ergonomics Society of Korea, Goomi, Korea, pp. 28–33 (2008). 54. C. H. Kim, S. Kim, J. Lee, D. Yoon, and S. Cho, A study of work-related musculoskeletal disorders at automobile industries in Korea, Proc. Sixth Annual International Conf. on Industrial Engineering-Theory, Application, and Practice, San Francisco, CA, pp. 18–20 (November 2001). 55. O. S. Ahn, Work environment and workload of farmers in four crop cultivation, PhD thesis, Seoul National University, Seoul, Korea, 2001. 56. Rural Development Administration, Agricultural workers’ health and management of agricultural tasks, 2008. 57. Y. H. Lee, J. H. Lee, K. S. Lee, K. R. Kim, and S. J. Lee, Ergonomic risk factors related to musculoskeletal symptoms in the vineyard workers, J. Korean Soc. Occup. Environ. Hyg. 18(2):122– 132 (2008). 58. Y. H. Lee, J. H. Lee, K. S. Lee, K. S. Kim, Y. K. Lee, Y. K. Kong, and S. J. Lee, Characteristics of lower-body posture of agricultural works in Korea, Proc. 41th Conf. the Korean Society of Occupational & Environmental Medicine, Busan, Korea, pp. 199–200 (November 2008).

1194    ◾    Occupational Ergonomics: Theory and Applications 59. H. C. Ryu, S. J. Lee, J. H. Lee, and K. S. Lee, Exposure rate of ergonomic risk factors related agricultural work, Proc. 41th Conf. the Korean Society of Occupational & Environmental Medicine, Busan, Korea, pp. 402–403 (November 2008). 60. K. S. Kim, K. R. Kim, H. C. Kim, and K. S. Lee, Risk assessment and symptoms of musculoskeletal disorders in melon farm workers, J. Korean Soc. Occup. Environ. Hyg. 16(4):385–397 (2006). 61. Y. H. Lee, J. H. Lee, K. S. Lee, K. S. Kim, Y. K. Kong, S. T. Shon, and S. J. Lee, Comparative analysis of ergonomic checklists by lower-body postures in Korean agricultural works, Proc. 41th Conf. the Korean Society of Occupational & Environmental Medicine, Busan, Korea, pp. 201–202 (November 2008). 62. Y. K. Kong, D. M. Kim, S. J. Lee, J. H. Lee, Y. H. Lee, K. S. Lee, and S. T. Shon, Evaluation of the effects of lower-limb postures on the subjective discomfort, heart rate, and EMGs of lower extremity muscles, J. Ergon. Soc Korea 28(1):9–19 (2008). 63. J. H. Kim, K. S. Lee, and S. K. Bae, The case study of the corporate ergonomics program at the automobile company, 2007 Spring Conf. of Ergonomics Society of Korea, 2007. 64. Y. Pyo and B. Y. Jeong, An implementation case of ergonomics program at a Shipbuilding company, J. Ergon. Soc. Korea 26(3):45–52 (2007).

Chapter

46

Overview of Ergonomic Needs and Research in India Rabindra Nath Sen CONTENTS 46.1 Introduction 46.2 Historical Background and Significance of Occupational Ergonomics 46.3 Some Aspects of Ergonomics Studies in India 46.3.1 Agricultural Ergonomics 46.3.1.1 Use of Tools and Implements and Their Design 46.3.1.2 Use of Pesticides 46.3.1.3 Use of Work Methods 46.3.1.4 Use of Modern Sophisticated Machines 46.3.2 Industrial Ergonomics 46.3.2.1 Ergonomic Design of Factory Buildings 46.3.2.2 Reduction of Heat Stress 46.3.2.3 Manual Materials Handling 46.3.2.4 Use of Ergonomic Designs of Tools and Implements 46.3.2.5 Mechanical Materials Handling 46.3.3 Application of Ergonomics to the Improvement of the Quality of Working Life 46.3.3.1 Consumer Ergonomics 46.3.3.2 Participatory Ergonomics 46.3.3.3 Ergonomics Application in Information Technology 46.3.3.4 Ergonomics Application for Low-Cost Improvements 46.3.3.5 Ergonomics Application in Transport Systems 46.4 International Symposia and Meetings on Ergonomics 46.5 Ergonomics Education and Training Program 46.6 Ergonomic Organizations in India and Their Roles 46.7 Ergonomic Design of Hospitals and Health Care Units References

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46.1  INTRODUCTION Ergonomics has been defined as the science, technology, and art of man at work [1]. Its aim is mainly to optimize human–machine–environment interactions to get the maximum efficiency, productivity, and improvement of the working conditions and working life of the workers. Though the basic principles of ergonomics have been practiced by workers in India from prehistoric times without the specialized knowledge of ergonomics, their formal application started only a few decades ago.

46.2 HISTORICAL BACKGROUND AND SIGNIFICANCE OF OCCUPATIONAL ERGONOMICS India is the second most populous country of the world, with about 920 million people, and its unemployment rate is huge even at the present time. A 3% annual population growth rate amounts to a 19-fold increase in a century. India was formerly a predominantly agricultural country, with about 80% of the population directly or indirectly involved in agriculture. Only since its independence from British rule and the initiation of the second five-year plan has it experienced industrial development. Hence, the application of occupational ergonomics is becoming more and more necessary. Among the many constraints in industrial development, financial constraints are the most important. Hence, in industrially developing countries (IDCs) such as India, the application of ergonomics must in the initial stages consider the implementation of improvements whose cost will be low or negligible. The significance of the use of occupational ergonomics in the progress and development of the country as a whole, not only in industry but also in agriculture and other areas, is unquestionable.

46.3  SOME ASPECTS OF ERGONOMICS STUDIES IN INDIA The work done in India regarding several ergonomics studies may also be applicable to other IDCs. Sen [1,2] and Kogi and Sen [3] reviewed the research work done in India in the following areas: 1. Energy expenditure of the workers in different types of jobs in various factories, and classification of heaviness of jobs on the basis of physiological responses 2. Anthropometric measurements in relation to the design of machines, tools, implements, and consumer products [1,2] 3. Problems of agricultural and other unorganized workers with special reference to manual materials handling [4–15] 4. Ergonomic solutions of problems in small-scale and cottage industries [16] 5. Low-cost improvements of working conditions, safety, health, and welfare of the workers [17]

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6. Postural analysis [18]

7. Training programs for workers, supervisors, trade union officials, managers, government executives, etc., to bring awareness of ergonomics to people at all levels including the general populace

Because of the huge population of India, any slight ergonomic improvement at the individual level would yield in total a very significant quantitative effect. In the unorganized sectors such as in agriculture and among manual laborers in various vocations—for example, masons, carpenters, blacksmiths, construction workers, household workers, and service workers such as laundry workers, barbers, handloom workers [19], cobblers, and about 8  million handicraft workers in India [20]—the use and application of ergonomics are much less common than in the organized sectors. This is due mainly to a lack of awareness of the basic principles, poor economic conditions, and reluctance to change existing and traditional work methods and tools. 46.3.1  Agricultural Ergonomics 46.3.1.1  Use of Tools and Implements and Their Design Several studies have been conducted for the improvement of the existing designs of tools, implements, and aids such as the sickle [5], plow [6,7], shovel [8,9], spade [10], combined shovel and hoe [11], and “float seat” [12] used in agricultural work. 46.3.1.2  Use of Pesticides In agriculture, the increased use of pesticides, mainly spraying without adequate protection, has increased the health hazards to agricultural workers by several folds. 46.3.1.3  Use of Work Methods Sen and coworkers [13–15,21,22] have studied the various traditional methods used in agricultural work. 46.3.1.4  Use of Modern Sophisticated Machines Traditional agricultural workers are unfamiliar with modern agricultural mechanized systems such as the use of the combine harvester and thresher, and modern work methods [13]. Similarly, traditional industrial workers are not acquainted with modern sophisticated industrial machinery, complex tools, and work methods. Many work-related diseases occur very frequently. There are very few statistical data on accidents in either agriculture or industry, especially from small-scale and medium-sized organizations [23]. Cultural, social, and economic differences make the problems of IDCs more difficult to solve than those of the developed countries. This poses a great challenge to professional ergonomists.

46.3.2  Industrial Ergonomics Like most other IDCs, India is traditionally agriculture-based and has evolved into an IDC only in the last few decades.

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46.3.2.1  Ergonomic Design of Factory Buildings There are several monographs on the design of factory building in cold climates. However, there have been practically no studies on the ergonomic design of factory buildings suitable for a tropical climate characterized by high ambient temperatures and high relative humidity. In any industry—big, medium-sized, or small—it is very important to plan much in advance the layout, design, and orientation of factory buildings. Sen [24] considered in detail the ergonomic design of factories suitable for the tropical climate of India. He stressed the importance of orienting the building to provide good natural ventilation and daylight, to reduce solar radiation by sun shades and double roofs, to circulate cooler underground air, and other factors. He emphasized the usefulness of a correct layout of the shop floor with respect to the positions of windows, fans, floor fans, materials, machines, workstations for different operations, storage, shipping, etc., so that efficient movement of personnel and a quicker flow of materials and products could be effected. It is imprudent to spend a huge sum of money to change a badly designed factory building at a later stage. It always pays to plan and design factory buildings ergonomically well in advance of the start of production. There is an acute shortage of housing for industrial workers. Whereas most of our public sector employers have tried to provide some housing for workers, the records of private sectors are not at all encouraging. 46.3.2.2  Reduction of Heat Stress Engineering control for the reduction of heat stress is very expensive in most cases. Hence, ergonomic designs of low-cost thermal barriers and low-cost personal protective clothing are of considerable importance.

Thermal barriers: In improving working conditions, various types of thermal barriers, personal protective devices, floor fans, “man coolers” (big, high-speed air circulating fans), etc., have been designed to reduce the effects of high heat stress, especially for workers in the steel industry, engineering work, glass factories, and the like. To protect against thermal radiation from furnaces, molten metal, slag, etc., in various factories, low-cost barriers against thermal radiation have been fabricated from two oxidized iron sheets, each about 1 m2 in size with a gap of 25 cm between them. The two sheets are held together by horizontal iron rods at four corners and at the middle. These portable thermal barriers are put on low-cost stands with different points of suspension to permit placing them between the sources of high thermal radiation and the workers. The hot air rises in the gap between the two sheets to significantly reduce the effects of thermal radiation [17]. Molten metal or slag channel cover: To reduce the thermal radiation from red hot molten metal or slag flowing in specific channels, small metal covers hinged on one side have been fabricated for the channels; these covers can be raised during maintenance and cleaning of the channels. The channel covers also act as guards against splashes of metal, sparks, etc., to effectively reduce the risks of burns and other accidents from spatters of molten metal [17].

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Personal protective devices: The acceptance of personal protective devices, equipment, and protective measures for technical devices depends substantially on their effective functionality and ergonomic design. Ergonomic designs of low-cost, washable, ventilated (by a “man cooler” at the back), vapor-permeable, flame-retardant, radiant-heat-reflecting type of special work clothing have been made for hot process workers such as furnace tenders and helpers in glass factories, and furnace tenders, teemers, chargers, cleaners, launderers, and bull-ladle operators in hot metal factories to reduce heat stress and physiological costs of work. The new special clothing was found to be 3–4 times more comfortable than the existing workwear, as revealed by worker polls. The use of this work clothing increased productivity in quality and quantity, especially during the summer months [3,25–27]. An ergonomically designed low-cost transparent face shield and fire-resistant, hard-toe safety boots with a hinged wooden sole are also suitable for workers working on the top of a coke oven battery and for furnacemen to protect them from thermal radiation and from injuries from metal splashes or sparks and to increase efficiency and productivity. Further research is necessary for ergonomic designs of similar low-cost personal protective devices for work situations having much more intense heat stress. Sen and Das [28] ergonomically designed a manual metal arc (MMA) welders’ screen and the protective work clothing for reducing the workload and risks of damage by ultraviolet radiation, shielding also against toxic fumes generated in the welding process, and reducing static local muscular fatigue. The improvement was due to the elimination of hand movements by the hand-held screen of the old design because the lower-jawcontrolled screen window protecting against ultraviolet rays was fixed in the helmet in the new design. The welder’s electro-optical protection filters and the welder’s curtain must conform to the needs of labor safety, comfort of wearing, and good ergonomic layout of the workplace. 46.3.2.3  Manual Materials Handling From time immemorial, one of the main problem areas in industry has been manual materials handling. The use of human labor is very extensive in IDCs like India. The use of machinery reduces the workload considerably for a worker and saves a lot of time, but it involves very high financial costs. It is often so expensive to mechanize and automate a manufacturing system that human adaptability makes it cheaper to use people for the awkward jobs such as materials handling and inspection. In a country with very cheap labor, a medium-sized or small-scale industry always uses workers in manual materials handling in the traditional manner. 46.3.2.4  Use of Ergonomic Designs of Tools and Implements Another way to bring about improvement is to use ergonomically modified designs of existing tools and implements so as to enhance their efficiency. Sen and coworkers [2,8–11] made attempts to improve the designs of the traditional shovel (Figure 46.1), spade, and shovel cum hoe to increase productivity and to reduce physiological costs to the workers by minimizing the degree of stooping required and enhancing leverage.

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FIGURE 46.1  An additional handle fitted at the base of a traditional shovel significantly reduces the

bending of the back and simultaneously increases the throwing distance by about 25%. A removable clip designed to temporarily hold the second handle when the shovel is used is not shown.

During the use of a standard shovel in lifting and handling materials such as sand and stone chips, the protracted bending or stooping posture causes backache and fatigue. An additional handle fitted at the base of the shovel significantly reduced the bending of the back and simultaneously increased the throwing distance by about 25% due to the improvement in leverage. Sen [29] similarly improved the existing designs of the beater and the ballast rake used for the manual maintenance of railway tracks. Efforts were also made to modify the designs of bullock-cart [30] and hand-pulled carts [31] and to use an ergonomically designed special harness [32] for the pullers. 46.3.2.5  Mechanical Materials Handling Special cart for moving heavy materials: In a company manufacturing ceramic bricks, an ergonomically designed special cart for transporting the bricks to the drying chamber on a metal plate was fabricated from low-cost bicycle parts and iron angles, which reduced the efforts of the workers by about 25% and increased productivity by about 15% [17].

Crane design: In mechanical materials handling, improvements were also made in the ergonomic design of a chain pulley system, forklift truck, platform truck, and overhead transport crane [28,33]. In many of the factories, there was simultaneous use of different designs of overhead transport cranes that had different types of controls and displays according to their positions, purpose of use, distance from the operator, etc., and there were many control–display incompatibilities. The need for the same worker to use different types of cranes on the same day resulted in an increase in the risk of accidents due to the greater chance of making a mistake in operating the controls. Sen and coworkers [28,33] suggested standardizing the positions of controls and displays and changing their locations so that the normal motion stereotypes are maintained and there are no risks of accident. There is scope for similar improvements in the design of tools, implements, trucks, crane cabins, etc.

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46.3.3 Application of Ergonomics to the Improvement of the Quality of Working Life The issue of the quality of working life will become the major concern of the people of India in the coming few decades. A more participative and humanizing approach to labor relations will be helpful only in the presence of a cooperative attitude of top management who should foresee the benefits of such work redesign. Ergonomists should undertake some studies relevant to improving the quality of working life. The challenge of change is faced by all big and small undertakings and enterprises. Much of the information collected and knowledge gained should encourage enterprises who embark on innovations to give due prominence to the human aspects of the proposed changes so as to ensure both the advances that are sought and continued improvement in the quality of working life of the people involved. 46.3.3.1  Consumer Ergonomics In most of the industries manufacturing products and consumer goods, much stress has been laid on the economic and aesthetic aspects, with very little or no attention paid to the functional and ergonomic aspects. A change in this attitude is desirable. 46.3.3.2  Participatory Ergonomics In industry, there are many problems that could easily be solved by collaborative, cooperative, and participatory efforts among ergonomists, factory managers, other officials, supervisors, foremen, and workers. Typical examples are the various low-cost modifications and improvements of existing work conditions, methods, and tools suggested by various experts in IDCs such as India, Sri Lanka, Indonesia, Singapore, Thailand, Malaysia, and the Philippines, for a project supported by the International Labour Organization [17]. Studies on participation of workers in the management of problems concerning work methods, machines, tools, and the work environment including the effects of noise [34,35] have shown that, as in Japan, job satisfaction and high morale are possible only in small working units. This is encouraging a growing number of industrial companies to redesign their larger organizations to form a collection of interlocking small groups. Considerable attention has been paid in recent years, by those interested, to change the attitude to work and restructure with innovations. Ergonomics is being applied to eliminate boring repetitive jobs [4], to create more interesting work, and thus to avoid physical and mental fatigue. 46.3.3.3  Ergonomics Application in Information Technology Though the development of modern management with radical improvements in information technology and instant communication has provided effective and dynamic corporate functioning and growth, yet it has also added to stresses and strains due to the operation of VDUs and other components of office automation. The stress includes all manners of pressure—physical, physiological, sociological, and/or a combination of all these and other

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relevant factors. It is well accepted that only a relaxed and healthy mind in a healthy body can cope with demanding responsibilities. With explosive use of information technology in IDCs like India, it is essential that ergonomically bad design aspects are excluded during the technology transfer from industrially developed countries. No system can claim to be the best; no organization possesses the one best form. There is a continuing interaction between all parts of the system. All parts of the system must therefore be developed together. The origin of a new philosophy of enterprise is to be found in the dramatic changes in India; these changes are evident in human relations in all aspects of living. Employers and/or governments must realize that though workers may lack scientific training, knowledge, or familiarity with technical jargon, it is they who experience the hazards at first hand. They must also recognize that it is often the pressure to produce more, and not recklessness or carelessness, that causes accidents and exposes workers to ill health. Impractical goals and unrelenting drives force the workers to work faster than the safe limits and thus experience accidents. Often trade unions too do not bother very much about shortcomings in enforcement of health and safety regulations. They are busy negotiating for higher wages and other monetary benefits. The trade union leaders should be put through special orientation and educational programs to make them aware of the importance and intricacies of safety and health issues. The message of the safety movement will have to reach every factory, farm, and even the workers on roadways and railways. Of late, there has been an increase in the number of accidents in the railway and road transport industries. Most of them could probably be avoided with better preventive action. Even work on farms, which used to be relatively safe from accidents, is becoming more and more hazardous because of the use of poisonous chemicals and pesticides and unsafe machines. 46.3.3.4  Ergonomics Application for Low-Cost Improvements In the industrial sector, Sen [17] has suggested low-cost improvements in the work process, work organization, and working conditions of various industries such as textile, soap, food processing, and engineering. Today many industrial managers believe that in order to achieve optimum efficiency in a plant, it should be kept rather smaller than what has generally been thought to be the optimum size. 46.3.3.5  Ergonomics Application in Transport Systems Railways transport: In railway transport, Sen and Ganguli [36,37] considered improvements in the design of both diesel and electric railway locomotive drivers’ cabins—control display aspects, the positions of primary and secondary controls and displays—the seating arrangements of the drivers and the assistants, and provision of their routine requirements. Sen [2,29] also stressed the need for ergonomic modifications of tools for railway track maintenance, existing ticket counters for punching tickets, the ergonomic design of signaling and signal control rooms, and arrangements of non-air-conditioned and airconditioned passenger coaches.

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Motor vehicle transport system: Sen and Nag [38] considered ergonomic improvements for double-decker public buses that were blind copies of London buses and consequently unsuitable for a tropical climate, having minimum facilities for ventilation and very high thermal radiation due to the metal body being heated by solar radiation. Sen and Nag [39] suggested several improvements such as higher ventilation, greater ease of passenger flow inside and out of the bus, better seating arrangements for the passengers as well as the driver, improved control and display arrangements for the driver, and greater access of the driver and the passengers into the bus. Public transport: Similarly, application of ergonomics is needed for better designs of cars, minibuses, trucks, and nonmotorized transport for rural areas such as cycle rickshaws, bullock carts, handcarts, cycle vans, and bicycles. Future research is also required on the design of roads and road signs to reduce the high rate of traffic accidents in India. Nonmotorized transport systems: Particularly in rural areas and in some urban and suburban areas in India, most passengers, goods, patients, etc., are transported in three-wheel cycle rickshaws manually operated by pullers [40]. Sen et al. [40] carried out studies on improving the design of hand-pulled and cycle rickshaws. Cycle rickshaws form one of the most widely used transport systems in both urban and rural areas throughout the country for short journeys. Cycle-rickshaw pulling is an important occupation for millions of people. The main advantages of using cycle rickshaws are as follows: 1. It causes almost no environmental pollution. 2. It is the only transport available in some instances and at some places. 3. It is not very costly. 4. It provides self-employment to a large number of people. In the years to come, research into improvements in the design of cycle rickshaws and the extent of such improvements should be ergonomically evaluated for implementing critical improvements from the anthropometric, physiological, and other relevant points of view. Design improvements in the line of new regenerative brakes, energy-storing devices, noncircular or elliptical or multisprocket drives, directional and positional stability, reduced cycle-rickshaw weight, lower center of gravity, and similar aspects constitute a few of the areas of possible improvement.

46.4  INTERNATIONAL SYMPOSIA AND MEETINGS ON ERGONOMICS In the international symposia on work physiology and ergonomics and on applied physiology and ergonomics held in Calcutta in 1974 and 1983, respectively, various problems faced by the developing countries were discussed [41]. A review of papers from a number of IDCs confirmed that the main ergonomics effects are directed toward the analysis of work problems and the implementation of cost-efficient workplace improvement.

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46.5  ERGONOMICS EDUCATION AND TRAINING PROGRAM In IDCs, ergonomics education at the school, college, and university levels is as important as bringing awareness to the individual and the public by using mass media such as radio, television, newspapers, and magazines. It is very important to make the contents of each educational program suitable for those for which it is intended. Ergonomic ways of using audiovisual aids, suitable examples through practical demonstrations, and the organization of popular exhibitions would go a long way toward bringing the principles of ergonomics to the persons concerned and elucidating the scope and benefits of its applications in day-to-day activities in all spheres of life. Invariably, the workers are the worst sufferers in all types of accidents. There has to be health and safety education for industrial workers as well as for supervisors and managers, both separately and jointly, particularly in accident-prone industries, such as the jute [42], mining, chemicals, fertilizer, engineering, and construction industries. There is as yet no such sustained educational program. Social attitudes and practices cannot be forced to change through strict legislation. What is needed is a genuine change of heart and a scientific approach through awareness and training. These take both time and a lot of effort and cannot be achieved overnight.

46.6  ERGONOMIC ORGANIZATIONS IN INDIA AND THEIR ROLES The pioneering research work on various aspects of work physiology and ergonomics such as anthropometry and energy costs of different activities including basal metabolic rate (BMR) of industrial workers was conducted in the Department of Physiology, Presidency College, Calcutta, beginning in 1953. Similarly, the Section of Physiological and Industrial Hygiene in the All India Institute of Hygiene and Public Health and the Department of Physiology, University Colleges of Science, Technology, and Agriculture, University of Calcutta started research on work physiology in the 1960s. Various institutions including the Defence Institutes of Physiology and Allied Sciences, Delhi; Industrial Physiology Division of Central Labour Institute, IIT and NITIE, Bombay; and the National Institute of Occupational Health, and NID, Ahmedabad, under the Government of India and other institutions supported by the Indian Council of Medical Research (ICMR), Indian Council of Social Research (ICSR), Council of Scientific and Industrial Research (CSIR), Department of Science and Technology (DST), and others carried out projects along similar lines. In 1970–1971, the University of Calcutta started the first postgraduate course in India on ergonomics and work physiology with limited resources. It is still the only university where this postgraduate specialty is taught, though several organizations run short-term orientation and refresher courses on work physiology and ergonomics. More centers of research and training should be established in the rural and urban sectors to apply the multidisciplinary approach of ergonomics to solve various problems of both the organized and unorganized sectors by optimizing the human–machine–­environment interactions to utilize human resources most efficiently without adverse effects. Scientific and professional societies like the Indian Society of Ergonomics (ISE) and academic institutions should thus play a very important role in exploring science and

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technology applications to generate awareness of multidisciplinary ergonomics, occupational health, safety, and the environment. As the interactions and the collaborative activities among the various institutions, industries, and agricultural institutes are very meager, steps must be taken to increase these interactions to have mutual benefits in solving pressing problems. Ergonomics should be introduced in a very simple form even in the school curricula. Students are capable of enthusiastically applying ergonomics in project work to produce successful designs for various purposes. An ergonomics survey of India similar in scope and function to the anthropological, zoological, and botanical surveys of India should be constituted to undertake comprehensive and large-scale surveys at the national level for the establishment of ergonomic norms of the Indian people. These should consider the different ethnic groups and habitual activities, static and dynamic body dimensions, abilities, performance, and environmental standards, for various working conditions.

46.7  ERGONOMIC DESIGN OF HOSPITALS AND HEALTH CARE UNITS The ergonomic design of hospitals and health care units for a large number of patients, in both rural and urban areas, is one of the most important areas that need the attention of ergonomists to improve the efficiency and productivity of health care personnel and the quality of patient care. It is similarly important to consider ergonomic designs for children and elderly people and for the physically and mentally handicapped and functionally impaired population of developing countries such as India. This includes design of buildings and rooms and of products, such as crockery and cutlery, and crutches and other mobility aids [43]. It is apparent that in the years to come the importance of ergonomics will increase in all spheres of life in the IDCs, depending on present approaches in the application, training, and research needs of ergonomics. Maintaining a balance between a few very expensive, high technology-oriented enterprises and a large number of low-cost small enterprises—all intending to bring benefits to the people—would be the key point in achieving improvement in the quality of working life in IDCs. The government of India in collaboration with the state governments should assume a supervisory and regulatory role in such matters.

REFERENCES 1. R. N. Sen, Application of ergonomics to industrially developing countries, Ergonomics 27:1021–1032 (1984). 2. R. N. Sen, Ergonomics—Science and technology of man at work—Its role in our national development, Proceedings of Indian Science Congress, 66th Session, Part II, Hyderabad, India, 1979, pp. 53–77. 3. K. Kogi and R. N. Sen, Third world ergonomics, Int. Rev. Ergon. 1:77–118 (1987). 4. R. N. Sen and P. K. Nag, Optimal work load for Indians performing different repetitive heavy manual work, Ind. J. Physiol. Allied Sci. 33:18–25 (1979). 5. R. N. Sen and D. Chakraborti, An ergonomic study on sickle designs for a reaping task in Indian agriculture, Proceedings of Ergonomics Society Conference, UK, published as Contemporary Ergonomics, E. D. Megaw, Ed., Taylor & Francis, London, U.K., 1989, pp. 313–317.

1206    ◾    Occupational Ergonomics: Theory and Applications 6. R. N. Sen and D. Chakraborti, A new ergonomic design of a “desi” plough, Ind. J. Physiol. Allied Sci. 38:91–105 (1984). 7. A. De and R. N. Sen, Ergonomic evaluation of ploughing process of paddy cultivation in India, J. Hum. Ergol. 15:103–112 (1986). 8. R. N. Sen and S. N. Bhattacharya, Evaluation of an ergonomically designed shovel, J. Physiol. Allied Sci. 38:150–154 (1984). 9. R. N. Sen and S. Bhattacharya, Development of an ergonomic design of a shovel from the viewpoint of increasing productivity in manual material handling in India, Project Report No. 23, Ergonomics Lab., Dept. of Physiology, Univ. Calcutta, Kolkata, India, 1976, pp. 1–14. 10. R. N. Sen, C. K. Pradhan, S. Basu, and A. K. Ganguli, An ergonomic evaluation of design of spades (“kodal”), Proceedings of Indian Science Congress, 66th Session, Part III, Hyderabad, India, 1979, pp. 6–7. 11. U. R. N. Sen and S. Sahu, An ergonomic design of a multi-purpose shovel-cum-“kodal” for manual material handling, Adv. Ind. Ergon. Safety 6: 561–566 (1994). 12. R. N. Sen and D. Chakraborti, A new ergonomic “float-seat” for improvement of paddy cultivation in India, in Ergonomics in Developing Countries, OSH Ser. No. 58, ILO, Geneva, Switzerland, 1987, pp. 419–427. 13. R. N. Sen and A. De, Ergonomics study of sheafing in paddy cultivation in India, Ind. J. Physiol. Allied Sci. 38:85–94 (1984). 14. A. De and R. N. Sen, A work measurement method for application in Indian agriculture, Int. J. Ind. Ergon. 10:285–292 (1992). 15. R. N. Sen, A. K. Ganguli, G. G. Ray, A. De, and D. Chakraborti, Tea leaf plucking—Workloads and environmental studies, Ergonomics 26:887–893 (1983). 16. R. N. Sen, Case studies to improve working conditions through technological choices in small and medium-sized (food processing, textiles and metal working) enterprises in West Bengal, in Improving Working Conditions in Small Enterprises in Developing Asia, K. Kogi, Ed., International Labour Office, Geneva, Switzerland, 1985, p. 158. 17. R. N. Sen, Examples of low-cost improvements in working conditions and environment, work methods, occupational health and safety at the enterprise level in West Bengal, in Low-Cost Ways of Improving Working Conditions—100 Examples from Asia, K. Kogi, W. O. Phoon, and J. E. Thurman, Eds., International Labour Office, Geneva, Switzerland, 1988, p. 179. 18. R. N. Sen and D. Pal, A new ergonomic method for postural analysis, in Biomechanics, K. B. Sahay and R. K. Saxena, Eds., Wiley, New Delhi, India, 1989, pp. 226–270. 19. R. N. Sen and D. Ghoshthakur, Ergonomic study on work-rest cycle, physiological responses and production rate of hand loom weavers, Ind. J. Physiol. Allied Sci. 38:47–53 (1984). 20. R. N. Sen and A. Kar, An ergonomic study on bamboo handicraft workers, Ind. J. Physiol. Allied Sci. 38:69–77 (1984). 21. R. N. Sen, A. K. Ganguli, G. G. Roy, A. De, and D. Chakraborti, Ergonomics studies of tea-leaf plucking operations—Criteria for selection and categorization, Appl. Ergon. 12:83–85 (1981). 22. R. N. Sen, A. K. Ganguli, G. G. Roy, A. De, and D. Chakraborti, A preliminary ergonomic study on tea plucking operations: Two leaves and a bud, TRA J. 27:74–80 (1980). 23. R. N. Sen and S. Gangopadhyay, Ergonomics study of accidents during manual material handling in factories of West Bengal, Proceedings of the 11th Asian Conference on Occupational Health, Bombay, India, 1989, p. 95. 24. R. N. Sen, Certain ergonomic principles in the design of factories in hot climates, Proceedings of the International Symposium on Occupational Safety, Health and Working Conditions, International Labour Office, Geneva, Switzerland, 1982, pp. 123–147. 25. R. N. Sen and N. C. Dutta, An ergonomic design of low-cost protective work clothing for furnace workers, in Ergonomics in Developing Countries, Occupational Safety and Health Series No. 58, International Labour Office, Geneva, Switzerland, 1987, pp. 222–223.

Overview of Ergonomic Needs and Research in India    ◾    1207   26. R. N. Sen, Personal protective devices for workers working in radiant and hot environments in India, Proceedings of the 2nd International Symposium on Clothing Comfort Studies, in Mount Fuji, Japan Research Association for Textile End-Uses, Osaka, Japan, 1991, pp. 123–142. 27. R. N. Sen, Special work-wear and protective clothing for Indian furnace workers, Proceedings of the International Conference on Human-Environment System, Pergamon, Tokyo, Japan, 1991, pp. 411–415; J. Therm. Biol. 18:677–681, 1993. 28. R. N. Sen and S. Das, Ergonomics, occupational health and safety improvements for the manual metal arc welders, Proceedings of the 1st International Symposium on Ergonomics, Occupational Health, Safety and Environment, Bombay, India, 1991, Indian Society of Ergonomics (ISE), Calcutta, India, 1993, pp. 97–102. 29. R. N. Sen, Ergonomics design of some tools for manual maintenance of railway tracks in India, Proceedings of the 10th International Ergonomics Congress, Sydney, Australia, 1988: Ergonomics in Developing Countries, Vol. 1, A. S. Adams, R. R. Hall, B. J. MePhee, and M. S. Oxenburgh, Eds., Ergonomics Society of Australia Inc., Baulkham Hills, New South Wales, Australia, 1988, pp. 227–229. 30. R. N. Sen and P. Chatterjee, An ergonomic approach to the design of Indian bullock-cart used for carrying load in the city of Calcutta, Project Rep. No. 140, Ergonomics Laboratory, Dept. of Physiology, Univ. Calcutta, Kolkata, India, 1986, p. 18. 31. S. R. Dutta and S. Ganguli, An ergonomic approach to the design of Indian hand-pulled carts (“Thelas”), Ind. J. Physiol. Allied Sci. 33:102–106 (1979). 32. R. N. Sen and S. Gangopadhyay, New Ergonomic Harness Design for Hand-Cart Pullers, Project Rep. No. 120, Ergonomics Laboratory, Univ. Calcutta, Kolkata, India, 1985, p. 20. 33. R. N. Sen, A. K. Ganguli, and D. Chakraborti, Some anthropometric considerations related to Indian railways locomotive drivers, Ind. J. Physiol. Allied Sci. 38:106–113 (1984). 34. R. N. Sen, Some studies on the physiological effects of noise, Proceedings of the Seminar on Higher Productivity through Building Insulation, Bombay, India, 1967, pp. 53–69. 35. S. K. Chatterjee, R. N. Sen, and P. N. Sana, Determination of the level of noise originating from room air conditioners, J. Heating Vent. J. Air Cond. 38:429–433 (1965). 36. R. N. Sen and A. K. Ganguli, An ergonomics analysis of railway locomotive driver functions in India, J. Human Ergol. 11:187–202 (1982). 37. R. N. Sen and A. K. Ganguli, Preliminary investigation into the loco-man factor on the Indian railways, Appl. Ergon. 13:107–117 (1982). 38. R. N. Sen and P. K. Nag, Are Calcutta public buses ergonomically designed? Ind. J. Physiol. Allied Sci. 27:156–157(1957). 39. R. N. Sen and P. K. Nag, Design ergonomics of some public buses in Calcutta, Proceedings of Indian Science Congress, 61st Session, Part IV, Nagpur, India, 1974, pp. 126–127. 40. R. N. Sen, S. Basu, and A. Goswami, An ergonomic design of hand-pulled rickshaw, Proceedings of Indian Science Congress, 66th Session, Hyderabad, India, 1979, pp. 8–9. 41. R. N. Sen and S. Bannerjee, Eds., Proceedings of the International Satellite Symposium on Work Physiology and Ergonomics, Calcutta, India, November, 1–3, 1974 (during the 24th World Congress of Physiological Sciences held at New Delhi). Ind. J. Physiol. Allied Sci. 33:1–145 (1979). 42. R. N. Sen and D. Majumdar, Ergonomics in relation to occupational safety and health in jute industries in eastern India, Proceedings of the 10th Asian Conference on Occupational Health, Singapore, 1982, pp. 289–298. 43. R. N. Sen and A. Dutta Gupta, Ergonomics study on rehabilitation of a bilateral below-elbow amputee, in Advances in Industrial Ergonomics and Safety, Vol. 6, F. Aghazadeh, Ed., Taylor & Francis, London, U.K., 1994, pp. 437–440.

Appendix A: Biomechanical Modeling of Carpet Installation Task Amit Bhattacharya CONTENTS A.1 Description of the Models A.1.1 Static 3-D Biomechanical Model A.1.2 Two-Dimensional Dynamic Model for Carpet-Stretching Task References

1209 1209 1213 1217

First, a 3-D model was developed to estimate the joint stresses associated with static postures commonly assumed by the carpet layers. Second, a 2-D model was developed for analyzing the dynamic carpet-stretching task. The results emphasize joint reaction forces and ground reaction forces.

A.1 DESCRIPTION OF THE MODELS A.1.1 Static 3-D Biomechanical Model A static link segment model was developed to aid in the estimation of joint reaction forces and muscle moments at six joints on each side of the body. This model has 12 element link segments. These links are foot, shank, thigh, upper arm, and lower arm of each side of the body, plus one for torso and one for head and neck. During the carpet-stretching activity, three points of the body touch the ground [1]. These anatomical sites for a right-legged person are leg foot, knee, and palm of the hand. In addition, the knee kicker tool used for the carpet-stretching task makes ground contact at its front and back ends (Figure A.1). For the determination of ground reaction forces at these five contact points, the following equations apply: The static equations of equilibrium are

Sum of z-direction forces =0

(A.1) 1209

1210    ◾    Appendix A: Biomechanical Modeling of Carpet Installation Task Ground reaction forces Rf at left foot (unknown) Rk at left knee (unknown) Rkk at the padded end of the kicker (unknown) Rp at the front end of the kicker (unknown) Rh at the left hand (unknown) Knee kicker

Rf

Rk

Rkk

Y

X

Rh Rp

Z

FIGURE A.1  Static free body diagram for carpet installation task.



Sum of moments about x-axis = 0

(A.2)



Sum of moments about y-axis = 0

(A.3)



R f (x f − x k ) = W1 (x1 − x k ) + W2 (x 2 − x k )

(A.4)

where R f is the ground reaction force at the left foot (N) xf, y f are x and y coordinates of R f (m) W1 is the weight of the left foot segment (N) W2 is the weight of the left shank (N) x1 → x12 are x coordinates of segments 1–12 (m) y1 → y12 are y coordinates of segments 1–12 (m) x k, yk are x and y coordinates of left knee (m) Equation A.4 is solved for R f. The remaining equations are 12

∑ ∑ W + (W Fz =



1

I =1

kk

− R p − R f ) − R k − R h − R kk = 0

(A.5)

12

∑M = ∑W y + W x



I I

kk

y kk − R p y p − R f y f − R k y k − R h y h − R kk y kk = 0

(A.6)

I =1 12

∑M = ∑W x + W y



I I

kk

x kk − R p x p − R f x f − R k x k − R h x h − R kk x kk = 0

I =1

Equations A.5 through A.7 are solved simultaneously for R k, R h, and R kk

(A.7)

Appendix A: Biomechanical Modeling of Carpet Installation Task    ◾    1211

where Rp is the ground reaction force at the front end of the kicker (measured by the force platform) (N) R k is the ground reaction force at the left knee (N) (unknown) R k, R kk, are ground reaction forces at the left hand and at the padded end of the kicker (N) (unknown) Wkk is the weight of the kicker (N) W1 → W12 is the weight of segments 1–12 (N) xp, y p are x and y coordinates of the front end of the kicker (m) x h, yh are x and y coordinates of the left hand (m) x kk, ykk are x and y coordinates of the padded end of the kicker (m) Once the ground reaction forces are calculated, the equations of static equilibrium are written for each of the 12 body segments, and the knee kicker and the head/neck segments. These are

Sum of Z or vertical direction forces = 0

(A.8)



Sum of moments about y-axis = 0

(A.9)

An example of static free body diagram for the right thigh is shown in Figure A.2A. Similar static free body diagrams for the other segments are drawn for the equations of static equilibrium. The static free body diagrams for the knee kicker and the head/neck segments are shown in Figure A.2B and C. R M

Hip

WL = weight of shank WF = weight of foot

WL

Wrist WUL

M

Knee WL + WF

WH R

RP (known)

RKK

(A)

CG of head

M

(B)

(C) Basic equations ΣFZ = 0

M1

WT

M2

R4

WH

ΣMY = 0

R3

M4

(D)

ΣMX = 0

R2

R1

M3

Y X

Z

FIGURE A.2  Static free body diagram for the individual link segment. (A) Right thigh. (B) Knee

kicker. (C) Head. (D) Trunk.

1212    ◾    Appendix A: Biomechanical Modeling of Carpet Installation Task TABLE A.1  Weight of Body Segmentsa Segment Weight of foot = WA Weight of calf = WK Weight of thigh = WH Weight of trunk = WS Weight of upper arm = WE Weight of lower arm = WW Weight of hand = WN a b

Weight

Percentage of Body Weightb

(N)

(lb)

0.014 0.046 0.097 0.486 0.027 0.014 0.006

11.20 36.81 77.61 388.87 21.60 11.20 4.80

2.52 8.28 17.46 87.48 4.86 2.52 1.08

For a subject of BW = 180 lb (800 N). Ref. [2].

TABLE A.2  Location of Segment Center of Gravity as a Function of Segment Length Segment Foot Calf Thigh Trunk Upper arm Lower arm Hand

Segment Length from Proximal Joint (m)

Definition of Segment

0.50 0.433 0.433 0.50 0.436 0.430 0.506

Lateral malleolus to head metatarsal II Femoral condyles to medial malleolus Greater trochanter to femoral condyles Greater trochanter to glenohumeral joint Glenohumeral axis to elbow axis Elbow axis to ulnar styloid Ulnar styloid to knuckle II middle finger

Source: Dempster, W., Space requirements of the seated operator, WADS-TR-55-150, Wright Patterson Air Force Base, OH, 1955.

The aforementioned generalized equations are used for the calculation of joint reaction force and the muscle moment at each body joint. A computer program written in IBM-PC BASIC for Equations A.4 through A.9 has built-in anthropometric tabular data (Tables A.1 and A.2) for segment weights as percent of body weight, and the location of segment center of gravity (CG) as percent of segment length (proximal and distal). This program first calculates the joint reaction forces and moments from the left ankle joint to the left hip joint. Then it calculates these values from the right ankle joint to right hip joint. After performing these calculations, the program determines the values of joint forces and moments from the right wrist joint to right shoulder joint and then for the left side of the body. Finally, for the checking of force (R1, R 2, R3, R4) and moment (M1, M2, M3, M4) balance at the four corners (right shoulder and hip joint and left shoulder and hip joint) of the trunk in association with the head/neck segment, a static free body diagram is used (Figure A.2D). For static equilibrium at the trunk and the head/neck segments, the program checks whether or not the sum of forces at all four joints equals the sum of weights of the trunk and the head/neck. Next, it checks whether all clockwise moments about the CG of the trunk equal the corresponding counterclockwise moments. For static equilibrium, these values are equal to each other.

Appendix A: Biomechanical Modeling of Carpet Installation Task    ◾    1213

Model inputs: These are body weight, Rp, W1 → W12, Wkk, X, → X12, Y1 → Y12, Z1, Z12, X k, Yk, Xp, Yp, X h, Yh, X kk, and Ykk. Model outputs: R f; R k; R h; R kk; X, Y, Z coordinates of segment CG; X, Y, Z coordinates of whole body CG; joint reaction forces (vertical) and moments (My) at all body joints; and force and moment check at the trunk segment. A.1.2 Two-Dimensional Dynamic Model for Carpet-Stretching Task This phase describes a model to outline the dynamic aspects of the carpet-stretching task, which requires the use of a knee kicker [3]. This is a six-segment, or link, model of the kicking side of the body. The segments are foot, shank, thigh, torso, upper arm, and lower arm. The head and the hand are not included in this model at this stage of the model development. This model assumes that the major body motion is in the sagittal plane (xy) and in the longitudinal direction (along the x-axis) (Figure A.3), and the inertial forces in the Y

Z

X

(0, 0, 0)

(A)

Knee kicker RYS CS

RXS Shoulder joint

WS RYH Hip joint CH

RXH

Ankle joint

RXA CA

RXK RYK WK CK

RYB RXB Elbow joint

C.G.

WH RYA CA

WE CE

CK RYK

RXK Knee joint

Wrist joint WW (RXE) Knee kicker

CW RYW RXW WKK

RHY

(RHX)

WA (B)

FIGURE A.3  (A) Schematic of coordinate system for this study. (B) Link segment model.

1214    ◾    Appendix A: Biomechanical Modeling of Carpet Installation Task

lateral direction (z-axis) are minimal. During the knee-kicking task, the kicking side of the body generally remains airborne until the impact phase, when the suprapatellar region of the knee makes contact with the padded end of the knee kicker. During the entire kicking cycle, the only point on the right side of the body that is in contact with the ground is the front end of the kicker. During dynamic knee-kicking experiments, we found that the padded end produces no (or negligible) ground reaction forces. Therefore, the ground reaction force at the front end of the kicker essentially provides an integrated effect of whole body weight shifts associated with knee kicking. This information is an important input for the determination of joint stresses and muscle moments for the right, or the kicking, side of the body. The lateral forces in the z-direction under the front end of the kicker are assumed insignificant in comparison to those in the vertical (y) and the horizontal (x) directions. It is realized that the body weight is also supported at the left or stationary knee and the left or stationary hand. However, it is assumed that the inertial effects along the lateral direction are minimal; therefore, ground reaction forces at these body contact points will affect mainly the joint stress calculations of the stationary, or left, side of the body. As a first attempt in the modeling of dynamic aspects of knee kicking, the previous assumptions are reasonable. During the experiment phase, these assumptions were validated. Figure A.4 is a static free body diagram showing the wrist joint–knee kicker segment. In the following, the hand weight is assumed negligible, and the wrist joint and the knee kicker are assumed stationary during each kicking cycle: RH x − R x (w ) + R xe = 0



RH y − R y (w ) − W(R ) = 0



(A.10) (A.11)



Taking moments around the CG of the kicker gives −C(w ) + R y (w ) × l + RH y × X1 + RH x × c + R x (w ) × b = 0



(A.12)



where RHy is the vertical ground reaction force at the front end of the kicker (measured with a force platform) (N) RHx is the horizontal friction force at the front end of the kicker (measured with a force platform) (N) Rx(w) Rxe

Wrist joint RHy b

C(w) Ry(w)

c

W(k) l

X1

FIGURE A.4  Static free body diagram for the wrist joint–knee kicker segment.

RHx

Appendix A: Biomechanical Modeling of Carpet Installation Task    ◾    1215

R xe is the impact knee force applied at the padded end of the kicker (in Equation A.12, the direction of force applied is assumed to be toward the right) (N) R x(w), Ry(w) are horizontal and vertical joint reaction forces at the wrist joint (N) W(k) is the weight of the kicker (N) C(w) is the muscle moment at the wrist joint (N-m) l is the horizontal distance between the CG of the kicker and the wrist joint (constant value, measured manually) (m) X1 is the horizontal distance between the CG of the kicker and the middle of the front end of the kicker (point 0) (constant value, measured manually) (m) c is the vertical distance between the bottom of the front end of the kicker and the CG of the kicker (constant value, measured manually) (m) b is the vertical distance between the wrist joint and the CG of the kicker (constant value, measured manually) (m) For the calculations of joint reaction forces and muscle moments, the following generalized equations are used [4]:



R x (j) − R x ( j − 1) + R xe ( j) = M( j) × A x ( j)

(A.13)



R y (j) − R y ( j − 1) − W( j) + R ye ( j) = M( j) × A y ( j)

(A.14)



C(j) = C( j − 1) − R x ( j − 1) × {L( j) − S( j)} × sin θ( j) + R y ( j) × {L(j) − S(j)} × cos θ(j) + R y (j) × S(j) × cos θ( j) + R ye (j) × S(j) × cos θ(j) − R x (j) × S(j) × sin θ( j)

− R xe (j) × S(j) × sin θ(j) + IG(j) × θ( j)



(A.15)

where R x, Ry are joint reaction forces in the x and y directions, respectively, at (j)th and (j − 1)th joints (N) R xe, Rye are externally applied forces in the x and y directions, respectively, at (j)th and (j − 1)th joints (N) A x, Ay is the linear acceleration in the x and y direction of the CG of the segment with respect to a fixed reference point (m/s2)  θ(j) is the angular acceleration of CG of the segment (rad/s2) θ(j) is the angular location of segment with respect to right horizontal, degrees W(j) and M(j) are weight (N) and mass (kg) of the segment S(j) is the location of CG of the segment with respect to the joint under study (m) L(j) is the segment length (m) IG(j) is the mass moment of inertia of the segment about its CG (N-m/s2)

1216    ◾    Appendix A: Biomechanical Modeling of Carpet Installation Task Ry

+ve Rx

+C +ve

Joint (j – 1) Rx(j – 1)

Center of gravity of the segment C(j – 1) Rye(j) C(j) Ry(j) Ry(j – 1) θ(j) W(j) Rx(j) Rxe(j) L(j) S(j) Joint(j)

M(j) . Ay(j) M(j) . Ax(j) IG(j) . θ(j)

FIGURE A.5  Schematic of generalized segment for force and moment equilibrium.

j = 1 to n = number of joints R x(0) = 0,  Ry(0) = 0,  C(0) = 0 For the static case  = 0 A x(j) = 0,  Ay(j) = 0  and  θ(j) Figure A.5 presents a generalized segment for force and moment equilibrium. The linear acceleration of CG of the segment with respect to the jth joint is given by the following generalized equation: AG x (j) = S(j) θ 2 ( j) cos θ(j) + (m) S(j) θ(j) sin θ(j)



AG y (j) = S(j) θ 2 ( j) sin θ(j) − (m) S(j) θ(j) cos θ(j)



(A.16)



(A.17)



The linear acceleration equation of CG of the generalized segment (in Figure A.6) with respect to a stationary reference point (usually a point of attachment) on the body is given by A x ( j) = AG x ( j) + linear x − acceleration of the jth joint with respect

to the point of attachment



Ay(j)

j+1

Center of gravity of the segment Ax(j) L(j)

S(j)

θ(j) j

FIGURE A.6  Schematic of generalized segment for linear acceleration calculation.

(A.18)

Appendix A: Biomechanical Modeling of Carpet Installation Task    ◾    1217

A y ( j) = AG y + y − acceleration of the jth joint with respect

to the point of attachment



(A.19)

In the carpet installation modeling study, the wrist joint is considered to be a stationary reference point or point of attachment. The second terms in the preceding two equations are therefore equal to zero for the first segment where j = 1 to n = number of joints m = +1 for counterclockwise rotation m = −1 for clockwise rotation  θ(j) is the angular acceleration of the segment CG; it can have either +ve or −ve values (rad/s2)  is the angular velocity (rad/s) θ(j) The remaining parameters have been explained previously. Equations A.10 through A.19 for the model were programmed in Microsoft FORTRAN for the IBM-PC laboratory computer. This program first starts calculating the values of A x(j) and Ay(j) from the point of attachment, the wrist joint, and continues on to the foot segment. Next, the program calculates joint reaction forces at the ankle, knee, and hip joints. And, finally, it calculates these values at the wrist, elbow, and shoulder joints. Model input: X and Y coordinates of body joints as a function of time, RHx, RHy, R xe, Rye, W(k), l, X1, c, b, M(j), subject height, and body weight.  and C(j). Model output: R x(j), Ry(j), A x(j), Ay(j), θ(j), θ(j), Developed by Amit Bhattacharya and his staff at the Biomechanics-Ergonomics Laboratory, University of Cincinnati Medical School, through a cooperative agreement with the National Institute for Occupational Safety and Health.

REFERENCES 1. A. Bhattacharya, M. Mueller, and V. Putz-Anderson, Quantification of traumatogenic factors affecting the knee: A worksite study of carpet installation, Applied Ergonomics 16(4):243–250 (1985). 2. W. Dempster, Space requirements of the seated operator, WADS-TR-55-150, Wright-Patterson Air Force Base, OH, 1955. 3. A. Bhattacharya, Biomechanical analysis of carpet installation task, ASME Conference, Cincinnati, OH, 1987. 4. D. Winter, Biomechanics of Human Movement, John Wiley & Sons, New York, 1979.

Appendix B: Ergonomics Checklists James D. McGlothlin and Amit Bhattacharya CONTENTS B.1 General Walkthrough Ergonomics Checklists B.1.1 General Workstation Design Principles B.1.2 Lifting and Lowering Tasks: Ergonomic Design B.1.3 Pushing and Pulling Tasks: Ergonomic Design B.1.4 Repetitive Hand Tasks: Ergonomic Design B.1.5 Selection of Ergonomic Hand Tools B.1.6 Carrying Tasks: Ergonomic Design B.1.7 Computer Workstation: Ergonomic Design B.1.8 Ergonomic Guidelines for Computer Operators B.1.9 Ergonomic Guidelines for Laboratory Employees B.1.10 Audit of Materials-Handling Risk Factors B.1.11 Audit of Repetitive Hand Tasks B.2 Walkthrough Ergonomics Checklist for Carpentry Tasks B.2.1 Worker Information B.2.2 Work Experience B.2.3 Repetitive Motion B.2.4 Postures B.2.5 Lifting Task B.2.6 Job/Task Requirement Data B.3 Symptoms Survey: Ergonomics Program Checklist B.3.1 Symptoms Survey Checklist B.3.2 Physical Examination Recording Form for Health Care Providers

1220 1220 1221 1221 1222 1223 1223 1224 1225 1226 1226 1227 1228 1228 1228 1229 1230 1235 1236 1237 1237 1238

1219

1220    ◾    Appendix B: Ergonomics Checklists

B.1  GENERAL WALKTHROUGH ERGONOMICS CHECKLISTS B.1.1  General Workstation Design Principles The use of the following general workstation design principles will help achieve an optimum match between the work requirements and operator capabilities. This, in turn, will maximize the performance of the total system while maintaining human comfort, well-being, efficiency, and safety: □ 1. Make the workstation adjustable, enabling both large and small persons to fit comfortably and reach materials easily. □ 2. Locate all materials and tools in front of the worker to reduce twisting motions. Provide sufficient work space for the whole body to turn. □ 3. Avoid static loads, fixed work postures, and job requirements in which operators must frequently or for long periods a. Lean to the front or the sides. b. Hold a limb in a bent or extended position. c. Bend the torso or head forward/backward more than 15°. d. Support the body’s weight with one leg. □ 4. Set the work height at 2 in. below the elbows for tasks requiring downward forces and heavy physical effort and 6 in. above the elbows for precision work. □ 5. Provide adjustable, properly designed chairs with adjustable seat height, adjustable up and down backrest, including a lumbar (lower-back) support, padding that will not compress more than an inch under the weight of a seated individual, and a chair that is stable to floor at all times (five-leg base). □ 6. Allow the workers, at their discretion, to alternate between sitting and standing. Provide floor mats/padded surfaces for prolonged standing. □ 7. Support the limbs. Provide elbow, wrist, arm, foot, and backrests as needed and feasible. □ 8. Use gravity to move materials. □ 9. Design the workstation so that arm movements are continuous and curved. Avoid straight-line, jerking arm movements. □ 10. Design so arm movements pivot about the elbow rather than around the shoulder to avoid stress on shoulder, neck, and upper back. □ 11. Design the primary work area so that arm movements or extension of more than 15 in. is minimized. □ 12. Provide dials and displays that are simple, logical, and easy to read, reach, and operate. □ 13. Eliminate or minimize the effect of undesirable environmental conditions such as excessive noise, heat, humidity, cold, and poor illumination.

The checklists in Section B.1 were developed by Dave Ridyard, CIH, CSP, CPE, Applied Ergonomics Technology, Jenkintown, Pennsylvania.

Appendix B: Ergonomics Checklists    ◾    1221

B.1.2  Lifting and Lowering Tasks: Ergonomic Design The following checklist should be used to eliminate the need to manually lift heavy or bulky materials, and reduce unnecessary bending, twisting, and reaching when lifting materials:

1. Optimize material flow through the workplace: □ □ Reduce manual handling of materials to a minimum. □ Establish adequate receiving, storage, and shipping areas. □ Maintain adequate aisle and access areas.



2. Eliminate the need to lift or lower manually: □ Life tables and platforms □ Life trucks □ Cranes and hoists □ Drum and barrel dumpers



3. Reduce the weight of the object: □ Reduce the weight and capacity of the container. □ Reduce the load in the container. □ Specify the quantity per container to suppliers.



4. Reduce the hand distance from the body: □ Change the shape of the object or container. □ Provide grips or handles.



5. Convert lift/lower combined with a carry to a push or pull: □ Conveyors, hand trucks, carts □ Ball caster tables

□ Elevated pallets □ Gravity dump systems □ Elevating conveyors □ Vacuum system

B.1.3  Pushing and Pulling Tasks: Ergonomic Design The following checklist should be used to eliminate manually pushing or pulling materials or to reduce the exertion hazard when materials are pushed or pulled:

1. Eliminate the need to push or pull: □ Conveyors □ Lift tables □ Slides or chutes □ Powered trucks





2. Reduce force required to push or pull: □ Reduce size and/or weight of load. □ Utilize four-wheel trucks or dollies. □ Utilize non-powered conveyors. □ Require that wheels and casters on hand trucks and dollies have the following: • Periodic lubrications of bearings • Adequate maintenance • Proper sizing (provide larger-diameter wheels and casters) □ Maintain floors to eliminate holes and bumps. □ Require surface treatment of floors to reduce friction.



3. Reduce the distance of the push or pull: □ Relocate receiving, storage, production, or shipping areas. □ Improve production to eliminate unnecessary material handling.

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4. Optimize technique of the push or pull: □ Replace pull with a push whenever possible. □ Use ramps with slope less than 10%. □ Provide variable-height handles so that both short and tall employees can maintain an elbow bend of 80°–100°.

B.1.4  Repetitive Hand Tasks: Ergonomic Design Workers may experience pain, discomfort, and disabling hand and wrist disorders such as carpal tunnel syndrome if the high number of repetitions is combined with abnormal wrist postures and excessive forces. The following checklist should be used as a guide for designing safe hand and wrist activities: □ 1. Reduce the number of repetitions per shift. Full or semiautomated systems should be used whenever possible. □ 2. Maintain neutral (handshake) wrist positions. Design jobs and select tools to reduce extreme flexion or deviation of the wrist. Avoid inward and outward rotation of the forearm when the wrist is bent to minimize stress to the elbow disorders (i.e., tennis elbow). □ 3. Reduce the force or pressure on the wrists and hands. Reduce the weight and size of objects that must be handled repetitively. Avoid tools that create pressure on the base of the palm which can obstruct blood flow and nerve function. Avoid repeated pounding with the base of the palm. Avoid repetitive, forceful pressing with the fingertips. □ 4. Design tasks so that a power grip rather than a finger pinch grip can be used to grasp materials. Note that a pinch grip is five times more stressful than a power grip. □ 5. Avoid reaching more than 15 in. in front of the body for materials: a. Avoid reaching above shoulder height, below waist level, or behind the body to minimize shoulder disorders. b. Avoid repetitive work that requires full arm extension (i.e., the elbow held straight and the arm extended). □ 6. Provide support devices where awkward body postures (elevated hands or elbows and extended arms) must be maintained. Use fixtures to relieve stressful hand/arm positions. □ 7. Select power tools and equipment with features designed to control or limit vibration transmissions to the hands, or alternatively design work methods to reduce time or need to hold vibrating tools. □ 8. Provide for protection of the hands if working in a cold or hot environment. Furnish a selection of glove sizes and sensitize users to problems of forceful over gripping when worn. □ 9. Select and use properly designed hand tools (e.g., grip size of tool handles should accommodate majority of workers).

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B.1.5  Selection of Ergonomic Hand Tools Poorly designed hand tools that combine repetitive forceful grip exertions with bent wrist postures can cause carpal tunnel syndrome and other cumulative trauma disorders. The ­following checklist can be used as a guide for selecting hand tools: □ 1. Maintain straight wrists. Avoid bending or rotating the wrists. Remember, bend the tool, not the wrist. A variety of bent-handle tools are commercially available. □ 2. Avoid static muscle loading. Reduce both the weight and size of the tool. Do not raise or extend elbows when working with heavy tools. Provide counterbalanced support devices for heavier tools. □ 3. Avoid stress on soft tissues. Stresses result from poorly designed tools that exert pressure on the palms or fingers. Examples include short-handled pliers and tools with finger grooves. □ 4. Reduce grip force requirements. A compressible gripping surface rather than hard plastic is best. □ 5. Whenever possible, select tools that utilize a full-hand power grip rather than a precision finger grip. □ 6. Maintain optimal grip span. Optimal grip spans for pliers, scissors, or tongs, measured from the fingers to the base of the thumb, range from 6 to 9 cm. Recommended handle diameters for circular-handle tools such as screwdrivers are 3–5 cm when a power grip is required and 0.75–1.5 cm when a precision finger grip is needed. □ 7. Avoid sharp edges and pinch points. Select tools that will not cut or pinch the hands even when gloves are not worn. □ 8. Avoid repetitive trigger-finger actions. Select tools with large switches that can be operated with all four fingers. Also, the use of the thumb is preferred to using a single finger for trigger action. Proximity switches are the most desirable triggering mechanism. □ 9. Protect hands from excessive heat, cold, and vibration. □ 10. Wear gloves that fit properly to enhance strength and dexterity.

B.1.6  Carrying Tasks: Ergonomic Design

1. Eliminate the need to carry by rearranging the workplace to eliminate unnecessary materials movement and using the following mechanical handling aids, when applicable: a. Conveyors (all kinds) b. Lift trucks and hand trucks c. Tables or slides between workstations d. Four-wheel carts or dollies e. Air or gravity press ejection systems



2. Reduce the weight that is carried by a. Reducing the weight of the object b. Reducing the weight of the container c. Reducing the load in the container d. Reducing the quantity per container to suppliers

1224    ◾    Appendix B: Ergonomics Checklists



3. Reduce the bulk of the materials that are carried by a. Reducing the size or shape of the object or container b. Providing handles or handgrips that allow materials to be held close to the body c. Assigning the job to two or more persons



4. Reduce the carrying distance by a. Moving receiving, storage, or shipping areas closer to production areas b. Using powered and non-powered conveyors



5. Convert carry to push or pull by a. Using non-powered conveyors b. Using hand trucks and push carts

B.1.7  Computer Workstation: Ergonomic Design The use of the following set of computer workstation design guidelines will maximize the performance of the computer operator while maintaining human comfort, well-being, efficiency, and safety. Note that adjustability of the workstation is the key: □ The keyboard and mouse surface should be height adjustable between 23 and 28 in. Both keyboard and mouse should be positioned at elbow height. □ Workstation width should be at least 30 in. (76 cm). Workstation height should adjust 23–30 in. (58.4–76.2 cm). □ Depth of the workstation should allow for screen, keyboard, and approximately 3 in. to serve as a wrist rest area. □ Edges of the work surface must be rounded and at least 1 in. (2.5 cm) thick to prevent stress on the arms and wrists. □ A wrist rest should be provided to enhance workstation adjustability. Π Knee room design considerations: • Knee room height should be a minimum of 26.2 in. (66.5 cm) for nonadjustable surface and 24 in. (70 cm) for adjustable surface. • Knee room width should be a minimum of 27 in. (76.2 cm). • Knee room depth should be a minimum of 23.5 in. (59.7 cm) knee level and 31.5 in. (80 cm) toe level. □ Chair design considerations: • Chair base should be five-point, on casters. Chair should swivel. • Chair should have an adjustable seat height adjustable to 16–20.5 in. (40–52.1 cm). • Seat size between 15 and 17 in. (38.1–43.2 cm) deep and 17.7 in. (45 cm) and 20 in. (51 cm) wide with a “waterfall” front edge. • Seat slope should be adjustable 0°–24° backward slope. • Seat pan and backrest should be upholstered. When seated, the seat pan and backrest should not compress more than 3/4 in.

Appendix B: Ergonomics Checklists    ◾    1225

• Backrest size should be 20 in. or higher (50.8 cm) and 13 in. wide (33 cm), backrest height should be adjustable between 3 and 6 in. (8–15 cm), and backrest tilt should be adjustable 30°. • Removable, height-adjustable armrests should be incorporated. • Backrest, if adjustable, should have a locking mechanism. □ Screens should be located directly in front of the operator at a distance of 16–22 in. (40.6–55.8 cm) for focusing at close range. The topmost line of the display should not be higher than the user’s eyes. Screens should be located at right angle to windows. □ Task lighting, rather than overhead lighting, should be provided to minimize glare. Work surfaces and walls should be furnished with nonglare (matte) finish.

B.1.8  Ergonomic Guidelines for Computer Operators The simple adjustments outlined in the following text may increase the comfort of your computer workstation. Consider the following to prevent musculoskeletal and visual fatigue:

1. Adjust the height of your work surface and the height of your chair so that your keyboard is at elbow height and your feet are flat on the floor. If the work surface is not adjustable, a footrest should be used when the feet do not rest flat on the floor.



2. Adjust the backrest of your chair so that it provides support to your lower back. Do not sit on the edges of the chair: rest your back against the backrest.



3. Position the screen directly in front of you. The distance between your eyes and the screen should be approximately 16–22 in.



4. Adjust the height of the screen so that your eyes are level with the top of the screen.



5. Tilt the screen to minimize glare. Tilting the screen will help reduce glare caused by bright overhead lights.



6. Draw drapes or shades and utilize task lighting rather than bright overhead lighting when working at the computer to reduce glare.



7. Use a document holder. Documents placed flat on the desk will cause you to lean forward and flex your neck, leading to fatigue and discomfort. The document and screen should be located at approximately the same distance to eliminate constant eye refocusing at varying viewing distances.



8. Keep the area under your desk clear for adequate leg and knee room.



9. When keying, rest your wrists and/or forearms, and keep the upper arms nearly vertical to prevent fatigue. Use a wrist rest, if necessary, to maintain your wrists, hands, and arms in a straight horizontal line.

10. Take frequent micro-breaks and stretch periodically to reduce the soreness and stiffness related to fixed, static work postures.

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B.1.9  Ergonomic Guidelines for Laboratory Employees

1. Position equipment and tools directly in front of your body to reduce twisting motions and reach distances.



2. Eliminate excessive reaches over 16 in.



3. Set the work height (hand height) at 2 in. below the elbows to minimize static muscle fatigue of the shoulders, neck, and back.



4. Maintain good seated posture. Adjust the backrest so that it provides firm support to your lower back. Do not sit on the edge of the chair.



5. Minimize static loads and fixed work postures. Avoid: a. Leaning to the front or sides b. Holding an extremity in a bent or extended position c. Tilting your head forward more than 15° d. Bending your body forward or backward more than 15° e. Supporting your weight with one leg 6. Support the limbs. Use elbow, wrist, arm, and backrests when needed.



7. Reduce the number of repetitive hand, wrist, and finger motions. The use of the thumb is preferred to the use of a single finger for trigger action. Motorized pipettes eliminate repetitive, forceful trigger-finger motions.



8. Maintain neutral (handshake) wrist postures. Design experiments so that the wrist does not need to be flexed forward, extended backward, or bent from side to side.



9. Reduce grip force requirements. Select pipettes with a compressible rather than hard plastic-gripping surface. Use tools that utilize a full-hand power grip rather than a more forceful precision finger grip.

10. Avoid pounding with the pipette to pick up tips. 11. Select tools which minimize stress on soft tissues. Stress concentrations result from tool handles that exert pressure on the palms or fingers. Examples include short-handle pliers and tools with finger grooves that do not fit the specific employee’s hand.

B.1.10  Audit of Materials-Handling Risk Factors The following items should be considered when evaluating new or existing materials-­handling equipment, processes, work activities, or workstations:

1. Does the task require any of the following activities? □ Lifting, lowering, or carrying more than 25 lb □ Lifting, lowering, or carrying objects that are too bulky to easily grip and hold close to the body □ Lifting, lowering, or carrying materials more than 50 times per shift □ Lifting above shoulder height or below waist level □ Lifting in cramped areas resulting in bending, reaching, and twisting □ Pushing/pulling carts, etc., that require large forces to get moving □ Maintaining a fixed or awkward work posture (e.g., overhead work, twisted or bent back, kneeling, stooping, or squatting)

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2. Do any of the following unsafe practices or conditions exist? □ Employees not following procedures (taking shortcuts, etc.) □ Employees not using appropriate materials-handling equipment □ Materials-handling equipment inadequate or damaged □ Materials improperly stacked, loaded, or banded on fork trucks



3. Do any of the following unsafe work area conditions exist? □ Unsafe (cracked or broken pavement, etc.) walking surfaces □ Poor housekeeping (wet, oily floors; debris; clutter) □ Poor layout of work area—crowding, congestion, excessive traffic □ Excessive noise, heat, humidity, cold, or poor illumination

Area audited:________________________________________________________________ Audited by: _________________________________________________________________ B.1.11  Audit of Repetitive Hand Tasks The following items should be evaluated when evaluating new or existing work activities requiring highly repetitive motions with the hands or wrists (i.e., manual packaging or inspection activities, and the use of hand tools):



1. Does the task require any of the following activities? □ Performing the same motion every few seconds with the hands or wrists. □ Repetitively shaking cartons, bottles, or other materials (repetitive bending of the wrists). □ Bending the wrists when working. The wrists should be maintained in a neutral (handshake) position. The job task should not require the wrists to be flexed forward, extended backward, or bent from side to side. □ Working for extended periods of time with awkward body postures (elevated hands and elbows, extended arms, reaching behind body). □ Exerting high grip forces with the hands. □ Using a pinch grip rather than a power (curled-finger) grip. □ Using the hand as a “hammer.” □ Repetitively reaching more than 16 in. in front of the body. 2. Do any of the following unsafe hand tool practices or conditions exist? □ Using vibrating or impact tools or equipment □ Using tools that require bending or rotating the wrists □ Raising or extending the elbows when working with heavy tools □ Using tools requiring repetitive trigger-finger actions, excessive grip forces, or excessive forceful exertions

Area audited: _______________________________________________________________ Audited by: _________________________________________________________________

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B.2  WALKTHROUGH ERGONOMICS CHECKLIST FOR CARPENTRY TASKS Site: ——————————————————————ID code: —————————— Date: ————————————————————————————————–——— Contact: —————————————————————— Phone: ————————— Ergonomist:———————————————————————————————— Job specialty observed: —————————————————— Job code: —————— Task description:——————————————————————————————— Total time of observation: ————————————— (h) Start:—————————— Stop:—————————— B.2.1  Worker Information Subject name: —————————————————————— SS#———————— Address: ————————————————————————————————–— Phone: ————————————————————————————————–—— Age: ————— years

Sex: M/F

Ethnic code: —————

Height: ————— ft

Weight: —————lb.

Union local: ————— Tool belt:

Years employed: ————— Yes/No

Tools used: —————

B.2.2  Work Experience (Yes = 2, No = 1) 1. High level of background noise?

Score Yes No÷ :———————

2. Frequent, loud impact noise?

Yes No÷ :———————

3. Exposure to vibration?

Yes No :———————

Body parts exposed ———————————————— Rank 4 = :————————— 4. Weather conditions: Cloudy/sunny

Temperature :———————°F wet/dry

Working surface: :———————

Comments /observations: ——————————————————————————— —————————————————————————————————————— The checklist in Section B.2 copyright © 1992, Greater Cincinnati Occupational Health Center, Cincinnati, Ohio. Developed by Amit Bhattacharya and his staff at the Biomechanics-Ergonomics Research Laboratory, University of Cincinnati Medical School, Cincinnati, Ohio, through a cooperative agreement with the National Institute for Occupational Safety and Health.

Appendix B: Ergonomics Checklists    ◾    1229

B.2.3  Repetitive Motion The following frequency periods and ratings are based on the analysis made during the observation period on the specific day of the ergonomic walkthrough: Torso

Repetition/Minute

Rating

Score

1.  Bending at waist (not lifting) Rating: 1. For less than nine repetitions/minute 2. For nine or more repetitions/minute 2. Stooping (bending with legs straight) Rating: 1. For less than six repetitions/minute 2. For six or more repetitions/minute 3. Turning/twisting of upper torso Rating: 1. For less than nine repetitions/minute 2. For nine and more repetitions/minute

————

× ———— = ———— +

————

× ———— = ————

Lower Extremities 1.  Squatting Rating: 1. For less than six repetitions/minute 2. For six or more repetitions/minute 2: Kneeling Rating: 1. For less than six repetitions/minute 2. For six or more repetitions/minute

Repetition/Minute

Upper Extremities/Wrist 1.  Cycle time Rating: 1.  For cycle time ≥30 s 2.  For cycle time