usachppm ergonomics program assessment tool - aiha home

US Army Center for Health Promotion & Preventive Medicine

USACHPPM Ergonomics ProgramUSACHPPM Ergonomics Program

Assessment Tool for Adverse

Mechanical Stress

Assessment Tool for Adverse

Mechanical Stress

OverviewOverviewDescribe the reasons for developing “another” ergonomic assessment tool

Describe the tool and how it is used to assess work-related musculoskeletal disorder (WMSD) risk

IntroductionIntroduction

Reasons for Developing the ToolReasons for Developing the ToolMany Army jobs expose workers to intense (adverse) mechanical stress

High WMSD Incidence Rate

Lack of Ergonomic Personnel

Deficiencies In Existing Tools


Adverse Mechanical StressAdverse Mechanical StressExposure to mechanical energy that has sufficient intensity/frequency/duration to be associated with a significant probability of producing injury or functional impairment


Adverse Mechanical StressAdverse Mechanical StressIntroductionIntroduction

HiHi

MedMed

LoLo

InjuryInjury WellnessWellnessHardinessHardiness

Mec

hani

cal S

tres

sM

echa

nica

l Str

ess

DysfunctionDysfunction

Exceeds physical Exceeds physical tolerance limitstolerance limits

Too weak to trigger Too weak to trigger adaptive changesadaptive changes


Adverse Mechanical StressAdverse Mechanical StressTypes of Medical Conditions


Muscle TearTendon RuptureLigament TearCartilage TearBone Fracture

Acute ConditionsAcute ConditionsMyositisTendonitisBursitisFasciitisStress Fx

Chronic ConditionsChronic ConditionsNerve- Compression

Neuropathy- EntrapmentDegenerative- DDD- DJD

Ergonomics Focus

Civilian Mechanical ExposuresCivilian Mechanical ExposuresIntroductionIntroduction

Work-RelatedRisk Factors

RepetitionRepetition

Contact StressContact Stress

HandHand--Arm VibrationArm Vibration Whole Body VibrationWhole Body Vibration

Forceful ExertionForceful Exertion Awkward PostureAwkward Posture

Military Mechanical ExposuresMilitary Mechanical ExposuresIntroductionIntroduction

WB VibrationWB Vibration

RepetitionRepetition

Contact StressContact Stress

Forceful ExertionForceful Exertion

HandHand--Arm VibrationArm Vibration

RecoilRecoil

Load CarryingLoad Carrying

JoltJolt

The ToolThe Tool

Features of Assessment ToolFeatures of Assessment ToolBasic Assessment Tool– Screening tool to identify potential risks

Ergonomic Assessment Matrices– Provide more detailed evaluation– Scoring (0 – 8 point scales) to

characterize the exposure/prioritize targets for mitigation

“Expert” consultation available

The IH Ergonomic Assessment ToolThe IH Ergonomic Assessment Tool

Ergo Risk Factors ConsideredErgo Risk Factors ConsideredThe IH Ergonomic Assessment ToolThe IH Ergonomic Assessment Tool

Frequent Repetition

Risk Factors

Awkward/ Fixed

Posture

Forceful Exertion

Lifting

Vibration


IH personnel will perform ergonomic assessments in addition to customary assessments

IH Ergo Assessment ProcessIH Ergo Assessment ProcessThe IH Ergonomic Assessment ToolThe IH Ergonomic Assessment Tool

DocumentResultsRisks?

Exposure Assessment

Matrices

Basic Ergonomic

Assessment

End Assessment

Y

N

BasicErgonomic Assessments

BasicErgonomic Assessments

OverviewOverviewObligates evaluator to examine work activities & identify ergonomic risk factors

Excludes tasks performed for less than two hours per day

Basic Ergonomic AssessmentBasic Ergonomic Assessment

OverviewOverviewThe Basic Survey contains one question in each of these areas:

Frequent RepetitionsAwkward Postures/Fixed PosturesForceful Hand ExertionsFrequent Forceful Manual Material HandlingVibration


Basic Ergonomic AssessmentSample -- Frequent Repetitions


AdvancedErgonomic Assessments

AdvancedErgonomic Assessments


Assessment ComponentsRepetitionPostureForceful Exertion

Vertical & Horizontal Push/PullForceful Hand Exertion

LiftingVibration

Hand-Arm VibrationWhole Body Vibration

Advanced Ergonomic AssessmentAdvanced Ergonomic Assessment

RepetitionExposure Matrix

RepetitionExposure Matrix

Frequent Repetition Risk Factor

Performing the same motion over and over again with little variationRepetitious movement may be a “pattern” of several motions which are repeated


• Score dependent upon body part used and type of motion performed Posture

Exposure Matrix

PostureExposure Matrix

Posture Risk Factor

Placing joints in non-neutral positionsAssuming fixed joint positions that do not include movement variation


• Select position from ranges in graphic

ForcefulHand Exertion

Exposure Matrix

ForcefulHand Exertion

Exposure Matrix


Hand Exertion Risk Factor

Performing hand activities that require powerful muscular contractions


• Score dependent upon body part used and type of motion performed Lifting

Exposure Matrix

LiftingExposure Matrix

Lifting Risk Factor

Using powerful muscular contractions to move objects from one location to another


• Score using lifting index based upon MIL-STD-1472F

Horizontal Push/Pull

Exposure Matrix


Exposure Matrix

Horizontal Push/Pull Risk Factor

Applying horizontal force against an object, excluding lifting/lowering actions


• Score using MAF based upon MIL-STD-1472F7 Vertical Push/Pull

Exposure Matrix

Vertical Push/PullExposure Matrix


Vertical Push/Pull Risk Factor

Applying vertical force against an object, excluding lifting/lowering actions


• Score using MAF based upon MIL-STD-1472F

Hand-Arm Vibration

Exposure Matrix

Hand-Arm Vibration

Exposure Matrix

Hand-Arm Vibration Risk Factor

Transfer of mechanical oscillations to the UE usually as a result of contact with powered tools, equipment or structures


• Identify exposure based upon value from ISO 8041

Whole Body Vibration

Exposure Matrix

Whole Body Vibration

Exposure Matrix

WB Vibration Risk Factor

Transfer of mechanical oscillations to the body usually as a result of contact with powered tools, equipment or structures


• Identify exposure based upon value from ISO 2631-1

Case StudyCase Study


Overview of Target TaskObjective: Assess Potential Musculoskeletal Injury Risks From Mechanical Exposures Related To:

Releasing Track Tension (subtask)when Removing M-88 Track Shoe


Task AnalysisJob: Repair M-88 Track Shoe

Task 1: Remove Track Shoe(s)– Release Track Tension– Remove Bolts From End Connectors– Separate Track– Position Track Shoe (by moving M-88)

Task 2: Install Track Shoe(s)


Assume 3 Hours Exposure for Case Study

Parse Subtask Into Elements

Release TensionUnscrew locknut to end of threads– Place wrench on locknut– Pull wrench up– Remove wrench from locknut


Identify Risk FactorsWhich RFs?


Repetition

Vibration

Forceful Exertion

Awkward Posture

Lifting

Repetition

Vibration

Forceful Exertion

Awkward Posture

Lifting

Next: Rate Task Using Appropriate EAMs

Idle, Little Exertion

Very Slow, Long Pauses

Steady, Infrequent Pauses

Slow, Steady, Brief Pauses

Rapid, Steady (Can’t Keep Up)

Rapid, Steady (Can Keep Up)

Score Frequent RepetitionsCharacterize “Overall” Task Motion?


Idle, Little Exertion

Very Slow, Long Pauses

Steady, Infrequent Pauses

Slow, Steady, Brief Pauses

Rapid, Steady (Can’t Keep Up)

Rapid, Steady (Can Keep Up)

Score Frequent RepetitionsInvolved Joints?


Shoulder

Neck

Wrist/Hand

Elbow

Forearm

Back

Shoulder

Neck

Wrist/Hand

Elbow

Forearm

Back


Find Freq Rep Scores

Score Frequent RepetitionsAdvanced Ergonomic AssessmentAdvanced Ergonomic Assessment

Shoulder & Elbow Rep ScoresBack Repetition Score

Score Frequent RepetitionsResults


Wrist/Hand

2BackNeck

Forearm1Elbow1Shoulder

ScorePart

Score Awkward PostureWhich Joint(s)?


Shoulder

Neck

Wrist/Hand

Elbow

Forearm

Back

Shoulder

Neck

Wrist/Hand

Elbow

Forearm

BackNote Marked Trunk Flexion

Score Awkward PostureAdvanced Ergonomic AssessmentAdvanced Ergonomic Assessment

Compare Angles

Scoring the Back


Forceful Hand

Vertical Push/Pull

Score ExertionWhich Type?


Forceful Hand


Vertical Push/Pull

Direction of ForceDirection of Force

Score ExertionHow Much Exertion Measured?


Trial 1: 221 lbsTrial 1: 203 lbs

Trial 1: 200 lbs

208 lbs(Average)=


Score ExertionHow Much Force Allowed?


166 lbsScore ExertionCalculate Exertion Percentage


= = = 125%x 100166 lbs208 lbs

MAFFMeasured x 100

Find Risk Score For Male Population

SummaryRepetition:Shoulder = 1, Wrist/Hand = 1, Back = 2

Awkward Posture:Back = 7

Forceful Exertion:Vertical Push/Pull = 4


Progress ReportProgress Report

IH Ergo Assessment Tool StatusThe assessment tool being field testedA mechanism has been established to monitor injury reports and identify the level of ergonomic assessment activity being perform at installationWe are hopeful that this program will improve efforts to identify ergonomic risks and drive down injury costs


USACHPPM Contact InformationDon Goddard, ErgonomistEmail: [email protected]: (410) 436-2736Katharine Neufeld, Industrial HygienistEmail: [email protected]: (410) 436-5476Steven Chervak, Email: [email protected]: (410) 436-7324



Questions?Questions?

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