| 2. |
- Hammarskjöld, Eva, et al.
(författare)
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Effect of short-time vibration exposure on work movements with carpenters' hand tools
- 1991
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Ingår i: International Journal of Industrial Ergonomics. - 0169-8141 .- 1872-8219. ; 8:2, s. 125-134
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to analyze the effect of ac ute vibration exposure on manual performance. Ten experienced healthy carpenters performed three standardized common tasks (nailing, sawing, screwing). EMG activity was recorded from six arm-shoulder muscles/muscle group using surface electrodes, and the performances were video-filmed. The subjects also reted their exertions. After ten minutes of standardized vibration exposure (50 Hz, 20 m/s2) the tasks were repeated. The number of work movements and the time taken for each task were recorded. In addition the quality of the work performed after the first and second trials was compared. Changes in muscle activity were mainly increased activity in trapezius. The most active muscles, with EMG mean values exceeding 10% EMGmax, were trapezius (mean values 9-21% EMGmax, infraspinatus (mean 6-18% EMGmax) and flexor digitorum (mean 15-21% EMGmax). Only rating perceived exertion while nailing was higher after vibration. Vibration exposure seemed to be very individually perceived. Short-time exposure did not seem to influence the performance of well-known tasks.
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| 3. |
- Johansson Hanse, Jan, 1954, et al.
(författare)
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Musculoskeletal Symptoms, Ergonomic Aspects and Psychosocial Factors in Two Different Truck Assembly Concepts
- 1993
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Ingår i: International Journal of Industrial Ergonomics. - 1872-8219 .- 0169-8141. ; 12:1-2, s. 35-48
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Tidskriftsartikel (refereegranskat)abstract
- The project was carried out as a multidisciplinary correlational study of two truck-axle assembly systems (System A and B). System A (the old system) could be characterized as an unpaced line assembly system, whereas the change to the new system, System B, involved a parallelized system with longer job cycle time. The study included all permanent assembly workers in the two systems (System A 17 workers, System B 28 workers). The purpose of this study was to evaluate the two systems with respect to ergonomic factors, psychosocial factors and self-reported musculoskeletal symptoms. The job cycles were studied by means of video observation. Each subject answered a questionnaire regarding musculoskeletal symptoms and physical and psychosocial environment. The assemblers in System B were more satisfied with the physical work environment (e.g. noise, air), but less satisfied with the psychosocial environment, and the period prevalence of musculoskeletal symptoms was not lower, compared with the assemblers in System A. Video observation techniques showed that deep forward flexion was less common, but that the work was more hand intense in System B. In System B, neck/shoulder symptoms were associated principally with physical work (load) variables, whereas low back symptoms were associated with psychosocial variables.
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