Approaches to the Assessment of Physical Exposure in VDT Work

Methods of Investigating WMSD and Methods of Investigating WMSD and VDT OperatorsVDT Operators

EpidemiologicIssue: How to measure “Exposure” (and

Health)?

LaboratoryIssue:What are relevant measures?

Methods of Investigating WMSD and Methods of Investigating WMSD and VDT OperatorsVDT Operators

Epidemiologic ApproachesQuestionnairesWork SamplingTechnical Exposure Assessment

Surface EMGPosture registration

Laboratory ApproachesSurface ElectromyogramsIndwelling Electromyograms

VDT Office EnvironmentVDT Office Environment

Work in VDT Office EnvironmentWork in VDT Office Environment

Talk with co-workerTalk with co-worker

Desk workDesk work

Talk on phoneTalk on phone

Interactive editingInteractive editing

FilingFiling

Filling out Filling out formsforms

Walk to ...Walk to ...

Graphic editing Graphic editing

Numeric pad entryNumeric pad entry

Physical Exposure for VDT OperatorsPhysical Exposure for VDT Operators

M

I-Distal Predictors of Exposure*Job design*Task variety*Workstation dimensions

II-Proximal Predictors of Exposure*Wrist Posture*Keystrokes force

III- (Internal)Exposure*Muscle activation*Tendon Load

Physical Exposure for VDT OperatorsPhysical Exposure for VDT Operators

InternalInternal ExternalExternalExposure Predictors of Exposure

Immediate/Immediate/ More Distant/More Distant/ Proximal Proximal Distal Distal

Posture

Force

RepetitivenessMuscleForce,Activation, Rest,Metabolism

TendonForce, FrictionMovement,Nutrition

Duration

(Median) NervePressure,Contact Stress,Friction, Stretch

Physical Exposure for VDT OperatorsPhysical Exposure for VDT Operators

III- Exposure

R/L Trapezius static Trapezius gaps R/L Wrist/finger

extensor static Wrist/finger extensor

gaps Tendon loads/strain Carpal canal pressure O2 tension Twitch force Ca++

II-Proximal Predictors of Exposure

Wrist posture Shoulder posture Neck posture Gaze angle %time sitting % steps walked Hand Activity Level Keystrike force

I-Distal Predictors of Exposure

Job title Workgroups Task variety # task transitions Workstation

dimensions Key depression force Control Psychological

demand