ErgonomicsErgonomicsErgonomicsErgonomics

The science of fitting the job to the workerThe science of fitting the job to the worker

MULTIDISCIPLINARY MULTIDISCIPLINARY NATURE OF ERGONOMICSNATURE OF ERGONOMICS

MULTIDISCIPLINARY MULTIDISCIPLINARY NATURE OF ERGONOMICSNATURE OF ERGONOMICSAnatomy and physiologyEngineering PsychologyEngineeringMedicineAnthropologyBiomechanics

Anatomy and physiologyEngineering PsychologyEngineeringMedicineAnthropologyBiomechanics

Benefits of ErgonomicsBenefits of ErgonomicsBenefits of ErgonomicsBenefits of Ergonomics

Decreased injury risk Increased productivity Decreased

mistakes/rework Increased efficiency

Decreased injury risk Increased productivity Decreased

mistakes/rework Increased efficiency

Decreased lost work days

Decreased turnover Improved morale

Decreased lost work days

Decreased turnover Improved morale

HISTORICAL PERSPECTIVEHISTORICAL PERSPECTIVEHISTORICAL PERSPECTIVEHISTORICAL PERSPECTIVE

Ramazzinni described posture and disease in 1700s

Before WWI labor surplus

During WWII labor scarce

WWII mass production of sophisticated equipmentReading Errors

Control-Display Relations

Ramazzinni described posture and disease in 1700s

Before WWI labor surplus

During WWII labor scarce

WWII mass production of sophisticated equipmentReading Errors

Control-Display Relations

EROGONOMIC CONCEPTSEROGONOMIC CONCEPTSEROGONOMIC CONCEPTSEROGONOMIC CONCEPTS

Tool design

Workstation Design

Material handling limits

Visual and auditory task design

Tool design

Workstation Design

Material handling limits

Visual and auditory task design

ENVIRONMENTAL ENVIRONMENTAL FACTORSFACTORS

ENVIRONMENTAL ENVIRONMENTAL FACTORSFACTORS

Noise

Vision

Thermal

Chemical

Noise

Vision

Thermal

Chemical

PSYCHOLOGICAL STRESSPSYCHOLOGICAL STRESSPSYCHOLOGICAL STRESSPSYCHOLOGICAL STRESS

Machine PacingShift Work

Morale

Machine PacingShift Work

Morale

PHYSICALPHYSICALPHYSICALPHYSICAL

PostureForceRepetitionManual Materials Handling

PostureForceRepetitionManual Materials Handling

TARGET REGIONSTARGET REGIONSTARGET REGIONSTARGET REGIONS

BackUpper ExtremitiesLower Extremities

BackUpper ExtremitiesLower Extremities

DESIGN AND DISEASEDESIGN AND DISEASEDESIGN AND DISEASEDESIGN AND DISEASE

POSTURE DISCOMFORTPOSTURE DISCOMFORT

Standing Legs, Feet, BackStanding Legs, Feet, Back

Sitting Neck, Back, ShouldersSitting Neck, Back, Shoulders

Reaching Shoulders, Upper ArmsReaching Shoulders, Upper Arms

Head Bent Back Cervical RegionHead Bent Back Cervical Region

Trunk Bent Forward Lumbar RegionTrunk Bent Forward Lumbar Region

STATIC EXERTIONSSTATIC EXERTIONSSTATIC EXERTIONSSTATIC EXERTIONS

Holding activitiesCarryingStandingPushing and pullingArms raised

Holding activitiesCarryingStandingPushing and pullingArms raised

EFFECTS OF STATIC EFFECTS OF STATIC EXERTIONEXERTION

EFFECTS OF STATIC EFFECTS OF STATIC EXERTIONEXERTION

When effort greater than or equal to 60 percent MVC blood flow almost completely interrupted.

15-20 percent MVC blood flow just about normal but still is associated with pain.

MVC less than or equal to eight percent can probably be maintained indefinitely.

When effort greater than or equal to 60 percent MVC blood flow almost completely interrupted.

15-20 percent MVC blood flow just about normal but still is associated with pain.

MVC less than or equal to eight percent can probably be maintained indefinitely.

WORKSTATION WORKSTATION GUIDELINESGUIDELINES

WORKSTATION WORKSTATION GUIDELINESGUIDELINES

Reduce static component and allow worker to use optimal posture

Optimal posture usually at midpoint of limbs range of motion

Avoid muscular insufficiency

Avoid forward reaches in excess of 16”

Elbows down close to the body flexor angle around 90 degrees

Reduce static component and allow worker to use optimal posture

Optimal posture usually at midpoint of limbs range of motion

Avoid muscular insufficiency

Avoid forward reaches in excess of 16”

Elbows down close to the body flexor angle around 90 degrees

WORKSTATION WORKSTATION GUIDELINES (continued)GUIDELINES (continued)

WORKSTATION WORKSTATION GUIDELINES (continued)GUIDELINES (continued)

Sit-Stand preferred but rarely seen

Use gravity do not work against it

Avoid the need for excessive head movement

Avoid compression Ischemia

Sit-Stand preferred but rarely seen

Use gravity do not work against it

Avoid the need for excessive head movement

Avoid compression Ischemia

WORKPLACE INDICATORSWORKPLACE INDICATORSWORKPLACE INDICATORSWORKPLACE INDICATORS

Performance deterioration…EngineeringQuality Control problemsAbsenteeism and turn-over…Human

ResourcesMusculoskeletal disorders…OSHA Logs

WC reportsComplaints of fatigue and discomfort

Performance deterioration…EngineeringQuality Control problemsAbsenteeism and turn-over…Human

ResourcesMusculoskeletal disorders…OSHA Logs

WC reportsComplaints of fatigue and discomfort

NIOSH LITERATURE SURVEY NIOSH LITERATURE SURVEY (NIOSH 97-141)(NIOSH 97-141)

NIOSH LITERATURE SURVEY NIOSH LITERATURE SURVEY (NIOSH 97-141)(NIOSH 97-141)

In 1994 32%32% of LWD cases (705,800) were result of overexertion or repetitive motion

367,424 Lifting 65% affected back

93,325 pushing/pulling (52%)

68,992 holding/carrying (58%)

92,576 repetitive motion, 55% wrist

83,483 NEC

In 1994 32%32% of LWD cases (705,800) were result of overexertion or repetitive motion

367,424 Lifting 65% affected back

93,325 pushing/pulling (52%)

68,992 holding/carrying (58%)

92,576 repetitive motion, 55% wrist

83,483 NEC

GROWING AWARENESS OF CTDsGROWING AWARENESS OF CTDsGROWING AWARENESS OF CTDsGROWING AWARENESS OF CTDs

Year Number of Repeated Trauma Cases

Total Number of Illnesses

1980 23,200 (18%) 130,200

1981 23,000 (18%) 126,100

1982 22,600 (21%) 105,600

1983 26,700 (25%) 106,100

1984 34,700 (28%) 124,600

1985 37,000 (30%) 125,400

1986 45,500 (33%) 136,800

1987 72,900 (38%) 190,200

1988 115,400 (48%) 240,900

TOP FIVE CTD INCIDENCE TOP FIVE CTD INCIDENCE INDUSTRIES BY RATEINDUSTRIES BY RATE

19901990

TOP FIVE CTD INCIDENCE TOP FIVE CTD INCIDENCE INDUSTRIES BY RATEINDUSTRIES BY RATE

19901990

Meatpacking

Poultry Processing

Household Refrigerator/Freezer

Motor Vehicle and Car Body

Men’s and Boy’s Trousers and Slacks

Meatpacking

Poultry Processing

Household Refrigerator/Freezer

Motor Vehicle and Car Body

Men’s and Boy’s Trousers and Slacks

TOP FIVE CTD INCIDENCE TOP FIVE CTD INCIDENCE INDUSTRY CLASSES BY INDUSTRY CLASSES BY

NUMBERNUMBER19901990

TOP FIVE CTD INCIDENCE TOP FIVE CTD INCIDENCE INDUSTRY CLASSES BY INDUSTRY CLASSES BY

NUMBERNUMBER19901990

Meat Products

Motor Vehicles

Men’s and Boy’s Furnishings

Miscellaneous Plastic Products

Aircraft and Parts

Meat Products

Motor Vehicles

Men’s and Boy’s Furnishings

Miscellaneous Plastic Products

Aircraft and Parts

Types of InjuriesTypes of InjuriesTypes of InjuriesTypes of Injuries

Muscle pain Joint pain Swelling Numbness Restricted motion Repetitive stress injury

Muscle pain Joint pain Swelling Numbness Restricted motion Repetitive stress injury

Repetitive motion injury

Cumulative trauma disorder

Musculoskeletal disorder

Repetitive motion injury

Cumulative trauma disorder

Musculoskeletal disorder

CUMULATIVE TRAUMA DISORDERSCUMULATIVE TRAUMA DISORDERSCUMULATIVE TRAUMA DISORDERSCUMULATIVE TRAUMA DISORDERS

Carpal Tunnel Syndrome Tendinitis Tenosynovitis Ganglion cyst Tennis Elbow

Carpal Tunnel Syndrome Tendinitis Tenosynovitis Ganglion cyst Tennis Elbow

Trigger Finger DeQuervian’s Disease Thoracic Outlet Syndrome Bursitis Synovitis

Trigger Finger DeQuervian’s Disease Thoracic Outlet Syndrome Bursitis Synovitis

A class of musculoskeletal disorders arising from repeated biomechanical stress due to ergonomic hazards. Common names for these disorders are:

A class of musculoskeletal disorders arising from repeated biomechanical stress due to ergonomic hazards. Common names for these disorders are:

Ergonomic Risk FactorsErgonomic Risk FactorsErgonomic Risk FactorsErgonomic Risk Factors

Repetition Awkward posture Forceful exertion Static posture

Repetition Awkward posture Forceful exertion Static posture

Mechanical contact stress

Temperature Vibration

Mechanical contact stress

Temperature Vibration

PSYCHOSOCIAL FACTORSPSYCHOSOCIAL FACTORSPSYCHOSOCIAL FACTORSPSYCHOSOCIAL FACTORS

LA Times HETA 90-013-2277

NIOSH PUBS 1-800-356-4674

US West HETA 89-299-2230

LA Times HETA 90-013-2277

NIOSH PUBS 1-800-356-4674

US West HETA 89-299-2230

PSYCHOSOCIAL FACTORSPSYCHOSOCIAL FACTORS(continued)(continued)

PSYCHOSOCIAL FACTORSPSYCHOSOCIAL FACTORS(continued)(continued)

Significant Findings

Fear of being replaced by computers

Enlarged Jobs

Uncertainty about job future

Work pressure

Lack of co-worker support

Lack of productivity standard

Lack of participation in decision-making

Perception management not value ergo

Significant Findings

Fear of being replaced by computers

Enlarged Jobs

Uncertainty about job future

Work pressure

Lack of co-worker support

Lack of productivity standard

Lack of participation in decision-making

Perception management not value ergo

Ergonomic ControlsErgonomic ControlsErgonomic ControlsErgonomic Controls

Engineering AdministrativeWork Practices

Engineering AdministrativeWork Practices

CONTROL TECHNOLOGYCONTROL TECHNOLOGYCONTROL TECHNOLOGYCONTROL TECHNOLOGY

Tool redesignWorkstation redesignJob methodsEarly detectionJob rotationMachine pacingMedical surveillance

Tool redesignWorkstation redesignJob methodsEarly detectionJob rotationMachine pacingMedical surveillance

REDUCTION OF REDUCTION OF REPETITIONREPETITION

REDUCTION OF REDUCTION OF REPETITIONREPETITION

Task Enlargement

Mechanization

Automation

Task Enlargement

Mechanization

Automation

REDUCTION OF EXTREME REDUCTION OF EXTREME JOINT MOVEMENT JOINT MOVEMENT

REDUCTION OF EXTREME REDUCTION OF EXTREME JOINT MOVEMENT JOINT MOVEMENT

Altering tool or controls

Workstation Design

Moving the Worker

Altering tool or controls

Workstation Design

Moving the Worker

REDUCTION OF FORCEREDUCTION OF FORCEREDUCTION OF FORCEREDUCTION OF FORCE

Reducing the force

Spreading the force

Better mechanical advantage

Reducing the force

Spreading the force

Better mechanical advantage

ADMINISTRATIVE CONTROLS ADMINISTRATIVE CONTROLS HAZARD PREVENTION AND HAZARD PREVENTION AND

CONTROLCONTROL

ADMINISTRATIVE CONTROLS ADMINISTRATIVE CONTROLS HAZARD PREVENTION AND HAZARD PREVENTION AND

CONTROLCONTROLRest-pauseIncrease number of employeesJob rotationPhysical conditioningRelief personnelMedical management

Rest-pauseIncrease number of employeesJob rotationPhysical conditioningRelief personnelMedical management

MATERIALS HANDLINGMATERIALS HANDLINGMATERIALS HANDLINGMATERIALS HANDLING

Lifting/Lowering

Pushing/Pulling

Carrying

Weights and Forces

Frequency of activities

Load Center of Gravity

Lifting/Lowering

Pushing/Pulling

Carrying

Weights and Forces

Frequency of activities

Load Center of Gravity

JOB RISK FACTORSJOB RISK FACTORSJOB RISK FACTORSJOB RISK FACTORS

Weight lifted

Position of load center of gravity

Frequency

Posture

Torso Flexion

Twisting

Arms extended

Weight lifted

Position of load center of gravity

Frequency

Posture

Torso Flexion

Twisting

Arms extended

JOB DESIGNJOB DESIGNJOB DESIGNJOB DESIGN

Can reduce one-third of compensable LBP

Minimize reach and lift distances

Keep off floor

Work station design

Frequency

Relax time standard

Rotation

Work-Rest allowances

Can reduce one-third of compensable LBP

Minimize reach and lift distances

Keep off floor

Work station design

Frequency

Relax time standard

Rotation

Work-Rest allowances

JOB DESIGN (continued)JOB DESIGN (continued)JOB DESIGN (continued)JOB DESIGN (continued)

Minimize Weight

Mechanical aids

Carton capacity

Balance contents

Convert:

Carry to push/pull

Push over pull

Use large wheels

Minimize Weight

Mechanical aids

Carton capacity

Balance contents

Convert:

Carry to push/pull

Push over pull

Use large wheels

TRAININGTRAININGTRAININGTRAINING

Focus on awareness and avoidance

Get object as close to body as possible

Planning

Use of handling aids

Back Schools

Strength and fitness important

Focus on awareness and avoidance

Get object as close to body as possible

Planning

Use of handling aids

Back Schools

Strength and fitness important

WORKPLACE USE OF BACK BELTSWORKPLACE USE OF BACK BELTSNIOSH 94-122NIOSH 94-122

WORKPLACE USE OF BACK BELTSWORKPLACE USE OF BACK BELTSNIOSH 94-122NIOSH 94-122

Insufficient Data that belts significantly reduce trunk loading

Insufficient data that wearing reduces risk of injury based on IAP and EMG

May strain cardiovascular systemInsufficient data that discontinuation of use

increases risk among healthy workers

Insufficient Data that belts significantly reduce trunk loading

Insufficient data that wearing reduces risk of injury based on IAP and EMG

May strain cardiovascular systemInsufficient data that discontinuation of use

increases risk among healthy workers

NIOSH does not recommend as tool for preventionNIOSH does not recommend as tool for prevention

ORGANIZATIONAL ORGANIZATIONAL INFLUENCESINFLUENCES

ORGANIZATIONAL ORGANIZATIONAL INFLUENCESINFLUENCES

Wage Systems

Quality Control

Management-Labor Relations

Machine-paced versus Self-paced work

Rest Breaks

Overtime

Shift Work

Wage Systems

Quality Control

Management-Labor Relations

Machine-paced versus Self-paced work

Rest Breaks

Overtime

Shift Work

RECOMMENDATIONSRECOMMENDATIONSRECOMMENDATIONSRECOMMENDATIONS

1. Identify Team Members 2. Identify problem jobs 3. Survey Employees 4. Develop Plan of Action 5. Select most feasible 6. Implement on small scale 7. Train 8. Measure response 9. Wider application or goto 4 10. Goto 2

1. Identify Team Members 2. Identify problem jobs 3. Survey Employees 4. Develop Plan of Action 5. Select most feasible 6. Implement on small scale 7. Train 8. Measure response 9. Wider application or goto 4 10. Goto 2

REDESIGN EFFORTREDESIGN EFFORTREDESIGN EFFORTREDESIGN EFFORT

Based on job analysis

Employee Feedback

Anthropometry

Fitting Trials (Prototyping)

Monitoring and Measurement

Based on job analysis

Employee Feedback

Anthropometry

Fitting Trials (Prototyping)

Monitoring and Measurement

REMEMBER WORKSTATION REMEMBER WORKSTATION DESIGN GUIDELINESDESIGN GUIDELINES

REMEMBER WORKSTATION REMEMBER WORKSTATION DESIGN GUIDELINESDESIGN GUIDELINES

Design where hands spend most of time

Normal reach envelope

Elbow height

Edge compression

Limit forward reaches to 16!

Design where hands spend most of time

Normal reach envelope

Elbow height

Edge compression

Limit forward reaches to 16!

WORK SITE ANALYSISWORK SITE ANALYSISWORK SITE ANALYSISWORK SITE ANALYSIS

Review OSHA 200 logEmployee interviewsPerformance Data (turnover, etc.)Video analysis of identified hazardous

positions

Review OSHA 200 logEmployee interviewsPerformance Data (turnover, etc.)Video analysis of identified hazardous

positions

Ergonomics Program Ergonomics Program ElementsElements

Ergonomics Program Ergonomics Program ElementsElements

Management leadership and employee participation

Hazard information and reporting

Management leadership and employee participation

Hazard information and reporting

Job hazard analysis and control

Training MSD management Program evaluation

Job hazard analysis and control

Training MSD management Program evaluation

REFERENCESREFERENCES

Applications guide for the revised NIOSH lifting equation

NTIS PB94-176930 (703) 487-4650 $12.00

NTIS PB91-226274 Scientific Documentation

Elements of Ergonomic Programs

NIOSH 97-117 1-800-35-NIOSH

Musculoskeletal Disorders and Workplace Factors

NIOSH 97-141

Work Practices Guide for Manual Lifting

NIOSH 81-122

REFERENCES (continued)REFERENCES (continued)

Cumulative Trauma Disorders: A Manual for MSDs of the Upper Limbs, Putz-Anderson

Fitting the Task to the Man, Grandjean

Taylor and Francis 1-800-821-8312

Methodological Limitations in the Study of VDT use and UEMDs

Gerr, Marcus, Ortiz, American J. Ind. Med. 29:649-656 (1996)

Ergonomics: The Study of Work, OSHA 3125,www.OSHA.gov

Dan Ortiz, Georgia Tech (404) 894-8276

www.oshainfo.gatech.edu