Department of Kinesiology - Biomechanics University of Waterloo, 2002 Effectiveness of a...

Department of Kinesiology - Biomechanics University of Waterloo, 2002

Effectiveness of a Participatory Ergonomics Effectiveness of a Participatory Ergonomics Intervention in Reducing Worker Pain Intervention in Reducing Worker Pain

Severity Through Physical and Severity Through Physical and Psychosocial Exposure PathwaysPsychosocial Exposure Pathways

Andrew Laing


Why Ergonomics Research?Why Ergonomics Research?

Effectiveness debatesEffectiveness debates Legislation and PoliciesLegislation and Policies Evidence based decisionsEvidence based decisions

What should should an ergonomist What should should an ergonomist focus on?focus on?


OUBPS Study ResultsOUBPS Study Results

Biomechanical Risk Factors:(Measured):“higher” peak shear“higher” peak hand force “higher” cumulative compression“higher” forward bending“higher” perceived phys demands

Psychosocial Risk Factors:(Perceived / questionnaire)“poorer” workplace social environment“higher” perceived education

(compared to peers)“lower” job control“higher” co-worker support“higher” job satisfaction

Individual Risk Factors:Prior WCB Low Back ClaimHigher body mass index (Ht. Wt.)

11.5%

4.7%31.4%

Biomechanical Risk Factors:(Measured):“higher” peak shear“higher” peak hand force “higher” cumulative compression“higher” forward bending“higher” perceived phys demands

Psychosocial Risk Factors:(Perceived / questionnaire)“poorer” workplace social environment“higher” perceived education

(compared to peers)“lower” job control“higher” co-worker support“higher” job satisfaction

Individual Risk Factors:Prior WCB Low Back ClaimHigher body mass index (Ht. Wt.)

11.5%

4.7%31.4%


Participatory ErgonomicsParticipatory Ergonomics

A process of ergonomic problem solving A process of ergonomic problem solving that incorporates input from each relevant that incorporates input from each relevant

workplace stakeholder group in workplace stakeholder group in identification of areas for improvement, identification of areas for improvement,

solution development, and implementation solution development, and implementation of physical and work organizational of physical and work organizational

changes in order to minimize risk of injury changes in order to minimize risk of injury and maximize productivity.and maximize productivity.


Studies on EffectivenessStudies on EffectivenessN = 11N = 11

Inconsistent outcome variablesInconsistent outcome variables Weak study designs (Control Groups: N = 2)Weak study designs (Control Groups: N = 2) Need for:Need for:

high quality longitudinal studieshigh quality longitudinal studies studies that describe and measure studies that describe and measure

interventionsinterventions studies that measure worker health studies that measure worker health

outcomesoutcomes

Ergonomics ProcessErgonomics Process

Ergonomics ProgramErgonomics Program

UW Ergonomics Process and Program Blueprint

1: Identify Opportunitiesfor Improvement:

Health Outcome, Risk FactorIdentification and Integration

2: Assess ErgonomicRisk Factors andPriorize Jobs for

Improvement3: Build Solutions

4: ImplementPrototype

5: EvaluatePrototype

6: AdoptSolution

ReactiveReactive ProactiveProactive

7b: EmployErgonomic

DesignCriteria andPurchasingGuidelines

7a: UseFeed--backfrom

Previousdesigns

andplants

Training and Education

Management of the Ergonomics Program

Evaluation Process

0: Start Up:

a) Establish Support

b) Team Formation

c) Initial Training

(Medical Management)

Documentation

++(Compliance Assurance)

Participation and Consultation

Management Support of Ergonomics and Resources

Corporate Ergonomics Policy

Ergonomic Tools, Techniques and Skills

Wells, Frazer, Norman,

Laing, 2001

Intervention Intervention Outcome Outcome Pathway:Pathway:

4: CHANGES IN PAIN / DISCOMFORT

(questionnaires)

2a: Workplace physical

interventions

2. PLANT LEVEL WORKPLACE INTERVENTIONS:

2b: Workplace psychosocial interventions

3b: Change in communication

levels and/or psychosocial

exposures (questionnaires)

3a1: Change in mechanical exposures (change specific

evaluations)

3a2: Change in Perceived Effort (questionnaires)

1: MANAGEMENT/ WORKFORCE ATTITUDES TO CHANGING THE

WORK ENVIRONMENT TO ADDRESS WMSDS

UW Participative Ergonomics Process and Program Blueprint

3. PRIMARY HEALTH

OUTCOMES


(questionnaires)


interventions







evaluations)





3. PRIMARY HEALTH

OUTCOMES


Physical Physical Change Change PathwayPathway


(questionnaires)


interventions







evaluations)





3. PRIMARY HEALTH

OUTCOMES

Psychosocial Psychosocial Change Change PathwayPathway



(questionnaires)


interventions







evaluations)





3. PRIMARY HEALTH

OUTCOMES

Evaluation Evaluation FrameworkFramework


ObjectivesObjectivesTo evaluate:

1. how the specific steps within the University of Waterloo Ergonomics Process and Program Blueprint may have influenced the effectiveness of the physical interventions implemented.

2. the effectiveness of a participatory ergonomics process in reducing pain severity levels through interventions aimed at reducing worker physical demands and mechanical exposures.

3. the effectiveness of a participatory ergonomics process in reducing pain severity levels through interventions aimed at enhancing workplace communication and reducing worker psychosocial risk factors.


If the proper pre-requisites exist, a If the proper pre-requisites exist, a participatory ergonomics intervention will participatory ergonomics intervention will

result in:result in:

Hypotheses:Hypotheses:1.1. Enhanced physical change projectsEnhanced physical change projects

2.2. Decreased exposure to physical risk Decreased exposure to physical risk factorsfactors

3.3. Decreased worker perceived effortDecreased worker perceived effort

4.4. Enhanced communication between Enhanced communication between workplace stakeholder partiesworkplace stakeholder parties

5.5. Increased worker perceived decision Increased worker perceived decision latitudelatitude

6.6. Increased worker perceived influenceIncreased worker perceived influence

7.7. Reduced pain severity reportsReduced pain severity reports

Measurement Tool:Measurement Tool:

Stakeholder FeedbackStakeholder Feedback

QuestionnaireQuestionnaire





Change Specific Change Specific EvaluationsEvaluations


METHODSMETHODS


Study SitesStudy Sites

Automotive Foam ManufacturerAutomotive Foam Manufacturer

Intervention (Whitby) / Control (Tilbury) Intervention (Whitby) / Control (Tilbury) PlantsPlants Subjects performing identical workSubjects performing identical work


Intervention ModelIntervention Model

Ergonomics ProcessErgonomics Process

Ergonomics ProgramErgonomics Program

UW Ergonomics Process and Program Blueprint

1: Identify Opportunitiesfor Improvement:

Health Outcome, Risk FactorIdentification and Integration

2: Assess ErgonomicRisk Factors andPriorize Jobs for

Improvement3: Build Solutions

4: ImplementPrototype

5: EvaluatePrototype

6: AdoptSolution

ReactiveReactive ProactiveProactive

7b: EmployErgonomic

DesignCriteria andPurchasingGuidelines

7a: UseFeed--backfrom

Previousdesigns

andplants

Training and Education

Management of the Ergonomics Program

Evaluation Process

0: Start Up:

a) Establish Support

b) Team Formation

c) Initial Training

(Medical Management)

Documentation

++(Compliance Assurance)

Participation and Consultation

Management Support of Ergonomics and Resources

Corporate Ergonomics Policy

Ergonomic Tools, Techniques and Skills


Team CompositionTeam Composition

Research Team n = 2

Management n =

5

Labour n = 4

Ergonomics Change Team


Input from stakeholder groups on Input from stakeholder groups on the effectiveness of final changes the effectiveness of final changes compared to initial prototypes.compared to initial prototypes.

Evaluation Tools:Evaluation Tools:Stakeholder FeedbackStakeholder Feedback


Evaluation Tools:Evaluation Tools:Change Specific EvaluationsChange Specific Evaluations

Evaluation of each change using: EMG, accelerometry, biomechanical modeling, worker ratings of preference expert opinion of UW researchers

Peak, Task Level, Shift Long, Overall Exposure Changes

Overall Time Weighted Changes =

Shift-Long Time Weighted Changes * Compliance * # of Workers

Affected At One Time / Total Workers in Department


Evaluation Tools: Evaluation Tools: QuestionnairesQuestionnaires

Perceived Effort: Borg CR-10 scale (Borg, 1990)

Communication Dynamics: 7 items, 5 point ordinal scale

Perceived Decision Latitude: Karasek’s JCQ (1985) – 9 items, 5 point ordinal scale

Perceived Influence: Greenberger (1981) – 11 items, 5 point ordinal scale

Reported pain severity body-part specific, 5 point ordinal scale


Qualitative observation of elements implemented, and perceptions of commitment to the participatory process.

Evaluation Tools: Evaluation Tools: Qualitative Process EvaluationQualitative Process Evaluation


Questionnaire Statistical Questionnaire Statistical Analyses:Analyses:

Perceived effort, decision latitude, influence, reported pain severity Between Plants: 2X2 ANOVAS (Pre/Post X

Whitby/Tilbury). Interaction effects were of primary interest

Communication Dynamics (only ‘Post’ responses) Between Plants: Chi Square

Perceived effort, decision latitude, influence, reported pain severity Between Plants: 2X2 ANOVAS (Pre/Post X

Whitby/Tilbury). Interaction effects were of primary interest

Communication Dynamics (only ‘Post’ responses) Between Plants: Chi Square


Study Time FrameStudy Time Frame (Months) (Months)

Team

Formation &

Training

T=0 months Q’air #1 (Pre)

T=1 month Change Projects / Change

Specific Evaluations T=1-11

months

Q’air #2 (Post)

T=11 months

0 11


RESULTSRESULTS


Results: Results: Participatory Influence on Participatory Influence on Physical Change ProjectsPhysical Change Projects

10 physical change projects implemented:10 physical change projects implemented:Zytec bin platformsZytec bin platforms Scoop knife handle wrapScoop knife handle wrap

Rear seat back platformsRear seat back platforms Sit-stand stoolSit-stand stool

Pack 1 – 8/rowPack 1 – 8/row Velcro straightening toolVelcro straightening tool

Zytec bin build toolZytec bin build tool Air sock repositionAir sock reposition

Trimmer handle wrapTrimmer handle wrap Anti-fatigue mattingAnti-fatigue matting

Based on worker input and feedback, the Based on worker input and feedback, the Blueprint participatory process enhanced the Blueprint participatory process enhanced the final changes implemented compared to the final changes implemented compared to the original prototypesoriginal prototypes

Results:Results:Mechanical ExposuresMechanical Exposures

Change Project

Estimated ‘Peak’ Exposure Changes

Estimated 4D Watbak Cumulative Exposure Changes / Task Level Time Weighted Cum Values

Combined LBPRI Changes

Full Shift Time Weighted Changes

Affects How Positions at Once / Positions in Dept

Estimated Compliance

Time Weighted Changes Considering Compliance and Job Rotation

Pack 1 – 8/row

Peak Dominant trap activity decreased by 19.8% (from 242 to 194 mV).

Average dominant trap activity decreased by 32% from 50 to 34 mV.

N/A Average dominant trap EMG value decreased by 23.8%.

1 / 11 100% APDF0.5 dominant trapezius EMG value decreased by 2.2%.

Zytec Bin Platforms

Joint shear decreased from 746 to 196N. No change as in LBPRIs as removing bottom parts with platform has almost the same posture as removing middle parts without the platform, and are peak loading postures.

LBPRIs - Cum Moment: 0.5 to 0.45, Cum Comp: .043 to 0.41, Cum Rshear: 0.53 to 0.47

Decrease from 0.39 to 0.34.

N/A 1 / 10 100% Combined LBPRI unchanged at 0.25.

Platform for Rear Seat Backs

LBPRIs: Moment - 0.36 to 0.28, Compression - 0.35 to 0.28, Rshear - 0.37 to 0.22

LBPRIs – Cum Mom.: 0.58 to 0.39, Cum Comp.: 0.48 to 0.38, Cum Rshear: 0.61 to 0.39

Decrease from 0.43 to 0.19.

N/A 1 / 10 100% Combined LBPRI dropped from 0.23 to 0.16.

Overall Changes Including Compliance and Job Rotation



When evaluated at the task level, the When evaluated at the task level, the physical ergonomic changes physical ergonomic changes implemented were successful in implemented were successful in reducing physical demands. reducing physical demands.

However, oHowever, overall calculations verall calculations (including compliance and job rotation (including compliance and job rotation schemes) showed only 2 changes with schemes) showed only 2 changes with substantial cumulative impacts.substantial cumulative impacts.


Results: QuestionnairesResults: QuestionnairesPopulation InformationPopulation Information

Pre-Post Matched Subjects for Questionnaires

Same Dept Pre-Post Matches

Total Population

Whitby Foam

44 58.7

Tilbury Foam

39 60.9

Total 83 59.7

75

64

167

Response Rate (%)


Results: Perceived EffortResults: Perceived Effort

Intervention

Control



4 body parts x 3 departments



No systematic changes in perceived No systematic changes in perceived effort at jobs where interventions effort at jobs where interventions were implemented.were implemented.


10 Psychosocial Elements introduced:User Trials One Minute Surveys

ECT Newsletter Suggestion Box

Bulletin Board Logo Contest

Shift Meetings Corporate Newspaper

ECT Meetings Steering Committee Meetings

Results: Psychosocial Results: Psychosocial InterventionsInterventions


Results: Communication DynamicsResults: Communication Dynamics

Since completing the last ergonomics project questionnaire (June 2001): Since completing the last ergonomics project questionnaire (June 2001):

1.1. Overall communication between labour and management has been enhanced.Overall communication between labour and management has been enhanced.

2.2. Communication between you and your fellow workers has been enhanced.Communication between you and your fellow workers has been enhanced.

3.3. Communication about general ergonomic issues has been enhanced.Communication about general ergonomic issues has been enhanced.

4.4. Communication about specific ergonomic improvement projects has been Communication about specific ergonomic improvement projects has been enhanced.enhanced.

5.5. Your opinion regarding specific ergonomic projects has been directly asked Your opinion regarding specific ergonomic projects has been directly asked more often.more often.

6.6. You have been encouraged to express your opinions about ergonomic issues You have been encouraged to express your opinions about ergonomic issues more often.more often.

7.7. You have expressed your opinions regarding ergonomic issues more often.You have expressed your opinions regarding ergonomic issues more often.

Since completing the last ergonomics project questionnaire (June 2001):

1. Overall communication between labour and management has been enhanced.

2. Communication between you and your fellow workers has been enhanced.

3. Communication about general ergonomic issues has been enhanced.

4. Communication about specific ergonomic improvement projects has been enhanced.

5. Your opinion regarding specific ergonomic projects has been directly asked more often.

6. You have been encouraged to express your opinions about ergonomic issues more often.

7. You have expressed your opinions regarding ergonomic issues more often.

Since completing the last ergonomics project questionnaire (June 2001):

1. Overall communication between labour and management has been enhanced.

2. Communication between you and your fellow workers has been enhanced.

3. Communication about general ergonomic issues has been enhanced.

4. Communication about specific ergonomic improvement projects has been enhanced.

5. Your opinion regarding specific ergonomic projects has been directly asked more often.

6. You have been encouraged to express your opinions about ergonomic issues more often.

7. You have expressed your opinions regarding ergonomic issues more often.


Results: Communication DynamicsResults: Communication Dynamics


Results: Qualitative Observations Results: Qualitative Observations of Psychosocial Interventionsof Psychosocial Interventions






Lack of Commitment to Participatory Process Observed












Lack of Commitment to Participatory Process Observed

Results: Qualitative Observations Results: Qualitative Observations of Psychosocial Interventionsof Psychosocial Interventions


Results: Decision LatitudeResults: Decision Latitude

Intervention

Control


Results: InfluenceResults: Influence

Control

Intervention


Results: Pain Severity - ComponentsResults: Pain Severity - Components

Intervention

Control


Results: Pain Severity – Plant WideResults: Pain Severity – Plant Wide

InterventionControl

Discussion: Discussion: Physical Change Physical Change

PathwayPathway

Distribution of WMSD symptoms Psychosocial Time delay


(questionnaires)


interventions






Compliance # of workers affected

Ergonomic change quality # of changes implemented

# of changes implementedExtent to which changes usedQuality of communicationsAmount of feedback acted on


evaluations)





3. PRIMARY HEALTH

OUTCOMES


PathwayPathway



(questionnaires)


interventions










evaluations)





3. PRIMARY HEALTH

OUTCOMES

10 physical change projects


PathwayPathway



(questionnaires)


interventions










evaluations)





3. PRIMARY HEALTH

OUTCOMES

Only 2 with substantial overall impacts



PathwayPathway



(questionnaires)


interventions










evaluations)





3. PRIMARY HEALTH

OUTCOMES


Only 1 position with sig. decreased perceived effort



PathwayPathway



(questionnaires)


interventions










evaluations)





3. PRIMARY HEALTH

OUTCOMES


Only 1 position with sig. decreased perceived effort

1 sig. decrease – leg pain in Components department



Discussion: Discussion: Psychosocial Psychosocial

Change PathwayChange Pathway



(questionnaires)


interventions










evaluations)





3. PRIMARY HEALTH

OUTCOMES





(questionnaires)


interventions










evaluations)





3. PRIMARY HEALTH

OUTCOMES

10 Psychosocial projects





(questionnaires)


interventions










evaluations)





3. PRIMARY HEALTH

OUTCOMES


Ergo communication sig. increased





(questionnaires)


interventions










evaluations)





3. PRIMARY HEALTH

OUTCOMES



Unchanged perceived decision latitude and

influence





(questionnaires)


interventions










evaluations)





3. PRIMARY HEALTH

OUTCOMES



Unchanged perceived decision latitude and

influence

Plantwide pain levels did not change


Potential Confounders:Potential Confounders:

Differential Study Site Experiences

Line speed changesNew plant managersContract negotiations


Conclusions:Conclusions: The Blueprint participatory model enhanced The Blueprint participatory model enhanced

the quality and impact of each of the final the quality and impact of each of the final physical change projects.physical change projects.

The Intervention Outcome Pathway model was The Intervention Outcome Pathway model was helpful in interpreting the results, and in helpful in interpreting the results, and in performing diagnostic evaluations of the performing diagnostic evaluations of the different elements involved in the different elements involved in the

ergonomic ergonomic intervention. intervention.


Conclusions:Conclusions:

Peak and task-level cumulative exposures were Peak and task-level cumulative exposures were decreased by each of the 10 change projects. decreased by each of the 10 change projects.

However, when shift long job demands and job However, when shift long job demands and job rotation schedules were considered, the rotation schedules were considered, the cumulative impacts were sufficient to reduce cumulative impacts were sufficient to reduce overall mechanical exposures for only two overall mechanical exposures for only two changes.changes.

Perceived Effort did not systematically changePerceived Effort did not systematically change This might, in part, explain the decreased pain This might, in part, explain the decreased pain

severity values in only one department.severity values in only one department.


Conclusions:Conclusions: The participatory ergonomics intervention The participatory ergonomics intervention

resulted in enhanced communication dynamics resulted in enhanced communication dynamics regarding ergonomic issues. regarding ergonomic issues.

Lack of commitment lead to lack of Lack of commitment lead to lack of significant change in perceived Decision significant change in perceived Decision Latitude and Influence.Latitude and Influence.

This, in part, explains the lack of changes in This, in part, explains the lack of changes in plant-wide Pain Severity levels.plant-wide Pain Severity levels.


Recommendations:Recommendations:

Additional research should be performed Additional research should be performed to determine: to determine: • the mechanical exposure changes necessary the mechanical exposure changes necessary

to reduce pain severity levels, to reduce pain severity levels, • the intensity of psychosocial interventions the intensity of psychosocial interventions

necessary to alter perceived decision latitude necessary to alter perceived decision latitude and influence levels, andand influence levels, and

• the magnitude of psychosocial risk factor the magnitude of psychosocial risk factor changes necessary to influence pain severity changes necessary to influence pain severity levels,levels,

• The success of the participatory process in The success of the participatory process in other worksites.other worksites.



The Ergonomics Change Team evaluated The Ergonomics Change Team evaluated in this study should:in this study should:• be encouraged to commit to the participatory be encouraged to commit to the participatory

change process, andchange process, and

• continue to implement physical and continue to implement physical and psychosocial ergonomic changes in hopes psychosocial ergonomic changes in hopes that additional interventions will involve that additional interventions will involve enough cumulative benefits to influence enough cumulative benefits to influence primary indicators of health. primary indicators of health.



To enhance chances of improved indicators To enhance chances of improved indicators of health, a corporate ergonomist should be of health, a corporate ergonomist should be involved to direct the team’s efforts.involved to direct the team’s efforts.


THANK YOUTHANK YOU

“You can buy people’s time, you can buy their physical presence at a given place, you can even buy a measured number of their skilled muscular motions per hour.

But you cannot buy loyalty, you cannot buy the devotion of hearts, minds, or souls. You

must earn them.”

- in Saari, 1989

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