Understanding Musculoskeletal Disorders
Musculoskeletal disorders (MSDs) are injuries affecting muscles, tendons, ligaments, nerves, and other soft tissues. They're among the most common and costly workplace injuries, accounting for nearly 30% of all worker's compensation costs.
The Scope of the Problem
By the numbers:
MSDs cause approximately 30% of all lost-time injuriesAverage MSD claim costs exceed $15,000 in direct costsIndirect costs typically add 2-4x additional expenseMost MSDs develop gradually over weeks or monthsCommon types:
Carpal tunnel syndromeTendinitisRotator cuff injuriesLow back disordersEpicondylitis (tennis/golfer's elbow)Trigger fingerRisk Factors for MSDs
MSDs result from exposure to ergonomic risk factors:
Physical Risk Factors
Repetition:
Performing the same motion repeatedlyHigh frequency of hand/arm movementsRepeated gripping, reaching, or twistingForce:
Lifting heavy objectsPushing or pulling loadsGripping with forcePinching small objectsAwkward Postures:
Working with arms above shouldersBending or twisting the torsoKneeling or squattingWrist deviationNeck flexion/extensionContact Stress:
Pressing body parts against hard surfacesUsing hands as hammersResting wrists on desk edgesVibration:
Whole-body vibration from vehiclesHand-arm vibration from power toolsContributing Factors
These don't directly cause MSDs but increase risk:
Cold temperaturesInsufficient recovery timeWork pace and deadlinesIndividual factors (prior injuries, fitness)Ergonomic Assessment Process
Step 1: Identify Problem Jobs
Use multiple data sources:
Injury and illness recordsWorkers' compensation claimsEmployee reports and complaintsJob demands analysisWalk-through observationsPrioritize jobs with:
History of MSD injuriesHigh exposure to risk factorsMany employees affectedEmployee concernsStep 2: Analyze Risk Factors
Assessment tools:
NIOSH Lifting Equation (manual lifting)Rapid Upper Limb Assessment (RULA)Rapid Entire Body Assessment (REBA)Strain Index (repetitive upper extremity work)Washington State Caution Zone ChecklistQuantify exposure:
Frequency of motionsDuration of posturesForce requiredWeight of objectsStep 3: Develop Controls
Apply the hierarchy of controls:
Engineering Controls (preferred):
Redesign workstationsProvide adjustable equipmentUse mechanical assistsModify tools and handlesAdministrative Controls:
Job rotationWork-rest schedulesTraining on proper techniquesGradual work conditioningPersonal Protective Equipment:
Anti-vibration gloves (limited effectiveness)Knee pads for kneeling workNote: Back belts not proven effective for preventionOffice Ergonomics
Workstation setup:
Chair:
Seat height allows feet flat on floorThighs parallel to floorLumbar support in curve of lower backArmrests at elbow heightMonitor:
Top of screen at or slightly below eye levelDistance approximately arm's lengthDirectly in front, not angledReduce glare from windows/lightsKeyboard and mouse:
Elbows at 90-degree angleWrists neutral (not bent up or down)Mouse at same level as keyboardAvoid reaching for mouseFor laptop users:
Use external keyboard and mouseElevate screen to proper heightConsider docking station for regular useIndustrial and Warehouse Ergonomics
Manual material handling:
Lifting:
Keep loads close to bodyLift with legs, not backAvoid twisting while liftingUse mechanical assists for heavy/frequent liftsStore frequently used items at waist heightPushing and pulling:
Push rather than pull when possibleUse carts with large wheelsKeep loads at push-bar heightMaintain cart wheels and bearingsAssembly work:
Provide adjustable workstationsPosition work at elbow heightRotate between different tasksUse fixtures to reduce holdingSupply tools that minimize forceImplementing an Ergonomics Program
Management Commitment
Demonstrate commitment by:
Allocating resources for improvementsIncluding ergonomics in safety policiesParticipating in assessmentsActing on recommendationsEmployee Involvement
Engage employees through:
Reporting discomfort and concernsParticipating in assessmentsTesting solutions before implementationProviding feedback on changesTraining
Train employees on:
Risk factors for MSDsEarly signs and symptomsReporting proceduresSafe work techniquesProper equipment adjustmentEarly Reporting and Response
Encourage early reporting:
Create non-punitive reporting cultureRespond quickly to concernsProvide medical evaluation when neededMake temporary accommodations availableMeasuring Program Effectiveness
Track these metrics:
Leading indicators:
Ergonomic assessments completedImprovements implementedTraining completionEarly reports of discomfortLagging indicators:
MSD injury ratesWorkers' comp claims for MSDsLost and restricted workdaysCosts associated with MSDsCommon Mistakes to Avoid
**One-size-fits-all solutions** - Different workers need different accommodations**Ignoring employee input** - Workers know their jobs best**Training-only approach** - Training without engineering controls has limited effect**Addressing symptoms not causes** - Fix the job, not just the worker**Expecting immediate results** - MSDs develop slowly and improve slowlyReturn on Investment
Ergonomic improvements typically pay for themselves:
Cost savings from:
Reduced injury claimsLower absenteeismDecreased turnoverFewer restricted duty assignmentsProductivity gains from:
Improved work methodsReduced reworkBetter qualityHigher employee engagementTypical ROI: Studies show returns of $2-$6 for every $1 invested in ergonomic improvements.
Conclusion
Musculoskeletal disorders are preventable through systematic identification of risk factors and implementation of effective controls. A successful ergonomics program requires management commitment, employee involvement, and a focus on engineering solutions.
Critical Dynamics provides comprehensive ergonomic assessments and program development services. Contact us to evaluate your workplace and identify opportunities for improvement.