Working postures and movements : tools for evaluation and engineering

Introduction ..................................................................................... 1 Nico J. Delleman, Christine M. Haslegrave, and Don B. Chaffin 1.1 Musculoskeletal Injuries ...............................................................................3 1.2 Studies of Posture and Movement .............................................................5 1.3 International Approaches for Evaluation and Engineering ...................8 1.3.1 ISO 11226 — Evaluation of Existing Work Situations ................9 1.3.2 prEN 1005-4 — Evaluation during a Design/Engineering Process............................................................................................... 11 1.4 Risk Assessment........................................................................................... 11 1.5 Overview of the Book.................................................................................13 References...............................................................................................................14 2 Anthropometry .............................................................................. 17 Introduction ...........................................................................................................17 2.1 Traditional Anthropometry........................................................................18 Bruce Bradtmiller, Claire C. Gordon, Makiko Kouchi, Hans W. Jürgens, and Young-Suk Lee Introduction ..................................................................................................18 2.1.1 Posture in Data Collection.............................................................19 2.1.2 Influence of Anthropometry on Posture .....................................21 2.1.3 Available Data..................................................................................23 Summary.......................................................................................................29 2.2 Three-Dimensional Anthropometry .........................................................29 Kathleen M. Robinette, Hein A.M. Daanen, and Gregory F. Zehner Introduction ..................................................................................................29 2.2.1 Why and When to Use Three-Dimensional Anthropometry....30 2.2.2 Measurement Techniques ..............................................................37 2.2.2.1 Three-Dimensional Devices ............................................37 2.2.2.2 Data Collection Methods.................................................39 2.2.3 Data Processing Methods ..............................................................40 2.2.4 Three-Dimensional vs. One-Dimensional Scanning..................43 Summary.......................................................................................................44 References...............................................................................................................45 3 Motor Behavior ............................................................................. 51 Nico J. Delleman Introduction ...........................................................................................................51 Postural Space ..............................................................................................52 Postural Strategy..........................................................................................53 3.1 Gazing............................................................................................................54 3.1.1 Oblique Gaze Direction..................................................................54 3.1.2 Vertical Gaze Direction...................................................................57 3.1.3 Horizontal Gaze Direction.............................................................58 3.2 Reaching........................................................................................................63 3.2.1 Reach Direction................................................................................63 3.2.2 Reach Distance.................................................................................67 3.2.3 Hand Trajectories ............................................................................67 Summary ................................................................................................................68 References...............................................................................................................68 4 Vision and Eyes............................................................................. 73 Wolfgang Jaschinski and Herbert Heuer Introduction ...........................................................................................................73 4.1 Basic Ocular Muscle Functions and Their Operating Ranges .............74 4.2 Viewing Distance .........................................................................................76 4.2.1 Concept of Ocular Resting Positions ...........................................76 4.2.2 Fixation Disparity: The Accuracy of Ocular Vergence..............77 4.3 Vertical Gaze Direction ...............................................................................80 4.4 User Preferences...........................................................................................80 Summary ................................................................................................................83 References...............................................................................................................84 5 Head and Neck.............................................................................. 87 Nico J. Delleman Introduction ...........................................................................................................87 5.1 Head Inclination ..........................................................................................89 5.2 Neck Flexion/Extension .............................................................................91 5.3 Recommended Gaze Inclination for VDU Operation .........................100 5.4 Neck Twisting.............................................................................................103 Summary ..............................................................................................................104 References.............................................................................................................105 6 Trunk ............................................................................................ 109 Jaap H. Van Dieën and Maury A. Nussbaum Introduction .........................................................................................................109 6.1 Definitions and Measurement ................................................................. 110 6.2 Trunk Anatomy.......................................................................................... 114 6.3 Effects of Trunk Posture ........................................................................... 117 6.3.1 Trunk Postures and Mechanical Load ....................................... 119 6.3.1.1 Tensile Tissue Strain ....................................................... 119 6.3.1.2 Net Moments...................................................................122 6.3.1.3 Muscle Activation ...........................................................124 6.3.1.4 Spinal Forces and Intra-Discal Pressure .....................126 6.3.2 Trunk Postures and Discomfort..................................................127 6.3.3 Trunk Postures and Fatigue ........................................................129 6.3.4 Trunk Postures and Low Back Pain...........................................131 6.4 General Evaluation Criteria .....................................................................132 Summary ..............................................................................................................134 References.............................................................................................................135 7 Pelvis ............................................................................................ 143 Introduction .........................................................................................................144 7.1 Sitting Behavior..........................................................................................144 Antonio Grieco, Giovanni Molteni, and Giovanni De Vito Introduction ................................................................................................144 7.1.1 Measuring Sitting Behavior.........................................................145 7.1.2 Influence of Task on Sitting Posture and Behavior .................148 7.1.3 Need for Variation in Posture during Work.............................153 7.1.4 Workstation Layout ......................................................................154 Summary.....................................................................................................155 7.2 Seating Concepts........................................................................................156 Tom Bendix and Bob Bridger Introduction ................................................................................................156 7.2.1 Optimizing Workplace Adjustments in Sedentary Work.......158 7.2.2 Seating Arrangements ..................................................................159 7.2.2.1 Seat Inclination................................................................159 7.2.2.2 Influence of a Backrest ...................................................162 7.2.2.3 Seat Height.......................................................................162 7.2.2.4 Work Surface Height and Inclination..........................163 7.2.2.5 Knee Support Chair........................................................164 7.2.2.6 Sit-Stand Workplace .......................................................165 7.2.2.7 Dynamics of Sitting ........................................................165 Summary.....................................................................................................167 7.3 Pelvis and Neighboring Segments..........................................................168 Bob Bridger and Tom Bendix Introduction ................................................................................................168 7.3.1 The Pelvis and Related Structures .............................................169 7.3.1.1 Pelvic Tilt and Lumbar Lordosis..................................170 7.3.1.2 Lumbar Spine, Sacrum, Pelvis, and Lower Limbs as a Linkage .....................................................................171 7.3.1.3 Pelvic Tilt in Different Body Positions ........................173 7.3.1.4 Effect of the Lower Limbs on Pelvic Tilt and Lumbar Angle .........................................................175 7.3.1.5 Pelvic Range of Movement in Different Body Positions ...........................................................................178 7.3.1.6 Lumbar Spine Range of Motion in Different Body Positions ...........................................................................179 7.3.2 Ergonomic Implications ...............................................................179 7.3.2.1 Sitting Posture: Improving the Posture of the Pelvis and Related Segments........................................179 7.3.2.2 Standing Posture: Improving the Posture of the Pelvis and Related Segments........................................181 7.3.2.3 Reclining and Lying Down: Improving the Posture of the Pelvis and Related Segments ............................182 7.3.3 Final Remarks ................................................................................182 Summary.....................................................................................................183 References.............................................................................................................184 8 Leg and Foot ................................................................................ 189 Introduction .........................................................................................................190 8.1 Pedal Operation .........................................................................................190 Xuguang Wang and Margaret I. Bullock Introduction ................................................................................................190 8.1.1 Force Control When Depressing a Pedal ..................................191 8.1.1.1 Ankle-Operated Pedals..................................................191 8.1.1.2 Leg-Operated Pedals ......................................................193 8.1.2 Kinematics of Lower Limb Movement during a Pedal Operation by Leg Thrusting........................................................194 8.1.3 Preferred Lower Limb Postures and Optimal Layout of Pedals ..............................................................................................199 8.1.3.1 Preferred Postures for Driving .....................................199 8.1.3.2 Optimal Layout of Automobile Pedals .......................200 8.1.3.3 Optimal Pedal Path to Minimize Spinal Movements.......................................................................201 8.1.4 Static Foot Strength and Perception of Foot Force..................207 Summary.....................................................................................................210 8.2 Flooring and Standing .............................................................................. 211 Rakié Cham and Mark S. Redfern Introduction ................................................................................................ 211 8.2.1 Epidemiological Findings: Impact of Flooring on Health Conditions ......................................................................................212 8.2.2 Findings of Relevant Published Studies ...................................212 8.2.2.1 Subjective Measures .......................................................214 8.2.2.2 Center of Pressure and Other Biomechanical Measures...........................................................................218 8.2.2.3 Localized Muscle Fatigue..............................................219 8.2.2.4 Leg Swelling ....................................................................220 8.2.2.5 Skin Temperature............................................................221 8.2.2.6 Task Performance............................................................222 8.2.2.7 Floor Material Properties...............................................223 Summary.....................................................................................................223 8.3 Slips and Falls ............................................................................................224 Mark S. Redfern, Rakié Cham, and Brian E. Moyer Introduction ................................................................................................224 8.3.1 Biomechanics of Slips ...................................................................225 8.3.1.1 Classifications of Slips....................................................226 8.3.1.2 Heel and Foot Dynamics...............................................226 8.3.1.3 Forces at the Shoe–Floor Interface ...............................227 8.3.1.4 Postural Reactions ..........................................................229 8.3.2 Environmental Factors in Slips and Falls .................................233 8.3.2.1 Human-Centered Approaches......................................233 8.3.2.2 Tribological Approach....................................................235 Summary.....................................................................................................237 References.............................................................................................................238 9 Shoulder Girdle and Upper Arm .............................................. 247 Introduction .........................................................................................................247 9.1 Shoulder Girdle..........................................................................................248 DirkJan Veeger and Frans C.T. Van der Helm Introduction ................................................................................................248 9.1.1 Anatomy .........................................................................................248 9.1.1.1 Bony Structures ...............................................................248 9.1.1.2 Muscle Function..............................................................250 9.1.2 Shoulder–Arm Kinematics...........................................................252 9.1.2.1 Measurement of Kinematics .........................................252 9.1.2.2 Three-Dimensional Kinematics ....................................253 9.1.2.3 Scapulohumeral Rhythm...............................................255 9.1.3 Biomechanical Modeling..............................................................257 Summary.....................................................................................................261 9.2 Upper Arm..................................................................................................262 Arne Aarås Introduction ................................................................................................262 9.2.1 Upper Arm Elevation ...................................................................263 9.2.2 Upper Arm Position with Respect to the Trunk......................268 9.2.3 Forearm Support ...........................................................................270 9.2.4 Forearm Posture ............................................................................273 9.2.5 Psychosocial Factors .....................................................................274 Summary.....................................................................................................275 References.............................................................................................................276 10 Forearm and Hand ...................................................................... 283 Introduction .........................................................................................................283 10.1 Hand–Handle Coupling ...........................................................................284 M. Susan Hallbeck and Roland Kadefors Introduction ................................................................................................284 10.1.1 Functional Anatomy .....................................................................285 10.1.2 Description of Hand Posture.......................................................286 10.1.3 Hand–Handle Characteristics .....................................................287 10.1.4 Grasp, Pinch, and Wrist Strength...............................................288 10.1.5 Gloves..............................................................................................291 10.1.6 Grip Span........................................................................................292 10.1.7 Implementation .............................................................................293 10.1.7.1 Demands in User Terms ................................................294 10.1.7.2 Ergonomic Factors ..........................................................295 10.1.7.3 Technical Demands.........................................................295 Summary.....................................................................................................296 10.2 Elbow, Forearm, and Wrist.......................................................................297 Richard Wells Introduction ................................................................................................297 10.2.1 Posture Definition .........................................................................298 10.2.2 Importance of Posture of the Elbow, Forearm, and Wrist for Comfort, Performance, and Injury.......................................298 10.2.3 Evaluation of Working Postures, Movements, and Forces ....298 10.2.4 Evaluation Criteria for Posture...................................................299 10.2.5 Interaction of Elbow, Wrist, and Finger Postures....................303 10.2.6 Effects of Movement.....................................................................303 Summary.....................................................................................................305 References.............................................................................................................306 11 Multiple Factor Models and Work Organization.................... 311 Introduction .........................................................................................................312 11.1 Multiple Factor Models ............................................................................312 Daniela Colombini and Enrico Occhipinti Introduction ................................................................................................312 11.1.1 Relevant Studies ..........................................................................312 11.1.2 General Assessment Model and Definitions...........................315 11.1.3 Methods and Indices for Risk Assessment .............................316 11.1.3.1 RULA and REBA...........................................................316 11.1.3.2 Strain Index....................................................................316 11.1.3.3 CTD Risk Index.............................................................318 11.1.3.4 ACGIH TLV ...................................................................318 11.1.3.5 OCRA Risk Index..........................................................320 Summary.....................................................................................................329 11.2 Variation and Autonomy..........................................................................330 Svend Erik Mathiassen and Marita Christmansson Introduction ................................................................................................330 11.2.1 What Is “Variation”?...................................................................332 11.2.2 Is Variation Related to Health? .................................................334 11.2.3 How Can Variation Be Measured? ...........................................335 11.2.4 Variation within an Occupational Task ...................................338 11.2.5 Variation between Tasks — Breaks in Static and Dynamic Work .....................................................................340 11.2.6 Breaks in Occupational Work....................................................342 11.2.7 Scheduled or Discretionary Breaks?.........................................343 11.2.8 Variation through Alternating Activities.................................345 11.2.9 Variation through Changed Schedules....................................346 11.2.10 Autonomy at the Individual Level...........................................346 11.2.11 Variation through Work Reorganizations................................347 11.2.12 Autonomy of Groups..................................................................351 11.2.13 Company Strategies, Variation, and Autonomy ....................352 11.2.14 A General Model of Variation and Autonomy.......................353 Summary.....................................................................................................355 References.............................................................................................................355 12 Force Exertion.............................................................................. 367 Christine M. Haslegrave Introduction .........................................................................................................367 12.1 Postural Behavior.......................................................................................371 12.1.1 Effects of Force Direction ..........................................................374 12.1.2 Effects of Workplace Layout and Environment ....................376 12.1.3 Work in Confined Spaces ..........................................................379 12.1.4 Freely Chosen Postures for Maximal Force Exertion ...........381 12.2 Strength Capability and Guidelines for Force Exertion......................386 12.2.1 Dynamic Tasks ............................................................................388 12.2.2 Lifting and Carrying ..................................................................389 12.2.3 Handling Live Loads .................................................................391 12.2.4. Using Manual Materials Handling Aids ................................392 12.3 Evaluation Techniques ..............................................................................395 Summary ..............................................................................................................396 References.............................................................................................................397 13 Performance ................................................................................. 403 Colin G. Drury and Victor L. Paquet Introduction .........................................................................................................403 13.1 Measuring Performance ...........................................................................404 13.2 Speed–Accuracy Trade-Off in Performance ..........................................406 13.3 Mechanisms and a Model of Posture and Performance.....................408 13.4 Studies of Posture and Performance ...................................................... 411 13.4.1 Field Studies ................................................................................412 13.4.2 Reaction Time and Tracking Tasks ..........................................413 13.4.3 Visual Inspection Tasks .............................................................414 13.4.4 Keyboarding Tasks .....................................................................416 13.5 Conclusions.................................................................................................419 Summary ..............................................................................................................419 References.............................................................................................................420 14 Digital Human Models for Ergonomic Design and Engineering.................................................................................. 425 Introduction .........................................................................................................426 Don B. Chaffin Motivation for Interest in Digital Human Models ..............................427 Digital Human Performance Prediction Modeling Is Different from More Common Human Analysis Modeling ...................428 Attributes of Digital Human Models When Used for Design...........429 14.1 The Jack Human Simulation Tool...........................................................431 Ulrich Raschke Introduction ................................................................................................431 14.1.1 Kinematic Representation in Jack...............................................431 14.1.2 Anthropometry in Jack.................................................................432 14.1.3 Posturing and Motion in Jack .....................................................434 14.1.4 Motion in Jack................................................................................434 14.1.5 Virtual Reality in Jack...................................................................435 14.1.6 Performance Models with Jack...................................................435 14.1.7 Low Back Injury Risk Assessment in Jack................................436 14.1.8 Population Strength Assessment in Jack...................................436 14.1.9 Fatigue Assessment in Jack .........................................................437 Summary of Jack Functions .....................................................................437 14.2 The SAFEWORK Human Simulation Tool............................................437 Mark Morrissey Introduction ................................................................................................437 14.2.1 Enterprise-Wide Human Modeling in SAFEWORK...............438 14.2.2 Anthropometry in SAFEWORK .................................................440 14.2.3 Realism of Skeletal Structure and Movement in SAFEWORK ...................................................................................441 14.2.4 Analysis Tools in SAFEWORK ...................................................443 14.2.5 Human Modeling Data Interoperability in SAFEWORK.......443 Summary of SAFEWORK Functions......................................................444 14.3 The RAMSIS and ANTHROPOS Human Simulation Tools...............445 Andreas Seidl Introduction ................................................................................................445 14.3.1 Anthropometrical Realization in RAMSIS................................445 14.3.2 Research of Posture and Movement Simulation for Cockpit Design with RAMSIS ..............................................447 14.3.3 Modeling of Vehicle Seating Spinal Postures and Belt Factors with RAMSIS ...................................................................447 14.3.4 Additional Functions in RAMSIS...............................................449 14.3.5 The Digital Human Model ANTHROPOS ...............................450 14.3.6 Design of ANTHROPOS..............................................................450 14.3.7 Working Posture Animation and Simulation with ANTHROPOS.......................................................................451 14.3.8 Additional Ergonomic Functions in ANTHROPOS................453 Summary of RAMSIS and ANTHROPOS Functions ..........................453 14.4 SAMMIE: A Computer-Aided Ergonomics Design Tool ....................454 J. Mark Porter, Russell Marshall, Martin Freer, and Keith Case Introduction ................................................................................................454 14.4.1 Functionality with SAMMIE .......................................................455 14.4.2 Development and Application of SAMMIE in Achieving Design for All.................................................................................455 14.4.3 Task Analysis in SAMMIE...........................................................459 14.4.4 Feedback and Result Reporting from SAMMIE......................460 Summary of SAMMIE Functions............................................................462 14.5 Boeing Human Modeling System...........................................................462 Steve Rice Introduction ................................................................................................462 14.5.1 Torso Modeling in BHMS ............................................................463 14.5.2 Predicting Reach Envelopes in BHMS.......................................463 14.5.3 Hand Tool Modeling in BHMS...................................................465 Summary of Boeing Human Modeling System Functions.................465 Summary of Digital Human Modeling...........................................................466 Don B. Chaffin Acknowledgments..............................................................................................468 References.............................................................................................................468