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Prevention of MSDs by workload optimization based on external and internal load assessment methods. Danuta Roman-Liu Central Institute for Labour Protection – National Research Institute. Work incapacity due to MSDs in 2003 - 2005.
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Prevention of MSDs by workload optimization based on external and internal load assessment methods Danuta Roman-Liu Central Institute for Labour Protection – National Research Institute
Work incapacity due to MSDs in relation to all incapacities in 2003 – 2005
Sectors with the highest rate of MSDs (according to Polish National Labour Inspectorate) • transportation • agriculture, fishing, forestry • mining • building industry, • wholesale and retail trade • hotels and restaurants, • health care
Risk factors for MSDs Work environment ٭Biomechanical factors posture force time sequences ٭Psychosocial factors job demands control social support Individual characteristics ٭Genetically determined inclination to diseases ٭Personality ٭Gender ٭Age ٭Physical capacity • Home environment • ٭Leisure time • ٭Diet • ٭Sport
External and internal load at the work stand External load can be assessed as a function of parameters describing performed task (body parts configuration, exerted force, time). Internal load is the reaction of musculoskeletal system to the external load. Methods: • NIOSH • OCRA • OWAS • LIMB Methods: • sEMG • ECG • HR • Oxygen consumption • Subjective assessment
Assessment of muscle load and fatigue using sEMG Placement of sEMG electrodes sEMG registered from four upper limb muscles
Packing stand involving repetitive tasks After intervention intervention Before intervention
Musculoskeletal load assessment on the Bale Opener work stand Workers at the „Bale Opener” work stand reported pain in wrist and hand. Musculoskeletal load of upper limb was assessed by means of sEMG.
[% MVC] [% MVC] 100 FCU RMG 90 80 70 60 50 40 30 20 [% of cycle time] [% of cycle time] 10 0 0 20 40 60 80 100 [% MVC] ECR [% of cycle time] Load level of examined muscles during each of cycle phases
Results Analysis of musculoskeletal load of forearm and hand shows that: ٭high musculoskeletal load of hand ٭lower, however still high, musculoskeletal load of forearm ٭the highest musculoskeletal load during tasks of cutting ties and this can cause upper limb pain ٭an important factor in the development of pain symptoms can be the shape of steering device, which is the main cause of musculoskeletal load in phases of steering the lift Indicators for ergonomic intervention ♦Changes of the shape of steering device by having it smaller and lighter with shape fitting the hand and decreasing the push button force. ♦Reduction of musculoskeletal load during cutting ties can be reached by implementation of scissors with pneumatic, hydraulic or electric aid.