Assessment of isometric muscle exertion in short-term considering task-rest schedule

Document Type : Article


1 School of Industrial Engineering, Iran University of Science and Technology, Tehran, Iran

2 Department of Architecture and Urban Development, Iran University of Science and Technology, Tehran, Iran


Numerous workers experience occupational diseases, especially musculoskeletal disorders, due to various physical, psychological, and individual factors. Among known risk factors for musculoskeletal disorders, work-rest patterns, and muscle fatigue are to be named. Assessment of muscle fatigue plays an important role, leading to a proper design for a work-rest program. This study was aimed to investigate isometric muscle strength in Iranian workers during repetitive activities based on gender and rest time. It has been attempted to present a model for isometric muscle strength. In a laboratory experiment, 31 students comprised of 19 males and 12 females participated, and muscle strength was recorded by a dynamometer. Minitab software results analysis proved that females' upper body muscles showed a higher level of resistance to fatigue rather than males. Furthermore, tests' results for each individual were more in line with cubic regression so that four models with a high R-Sq index (at least 94.4%) and high R-Sq (adj) index (at least 77.8%) were presented to predict isometric muscle strength in short-run. Finally, it has been suggested to use male workers for repetitive activities with a high workload and enough rest time and use female workers for repetitive activities with low workload and high frequency.


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