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Factors involved in strain-induced injury in skeletal muscles and outcomes of prolonged exposures.
J Electromyogr Kinesiol 2004 Feb; 14(1):61-70
Repetitive motion disorders can involve lengthening of skeletal muscles to perform braking actions to decelerate limbs under load often resulting in muscle strains and injury. Injury is a loss of isometric force (weakness) requiring days to recover. The capacity of skeletal muscle to tolerate repeated strains is dependent on multiple factors including individual variation. The most important factors producing muscle strain injury are the magnitude of the resisting force (peak-stretch force) and the number of strains. Other factors such as muscle length and fiber type contribute to the susceptibility to injury as well, but to a lesser degree. Strain injury can also lead to inflammation and pain. Chronic exposure to repeated strains can result in fibrosis that is not completely reversed after months of rest. Long rest times appear to be the only factor reported to prevent inflammation in rats following repeated strain injury. Further understanding of the mechanism for prevention of histopathologic changes by long rest times should provide a rationale for prevention of negative outcomes.
Muscles; Musculoskeletal system; Skeletal system; Injuries; Muscle tissue; Exposure levels; Repetitive work; Motion studies; Injury prevention; Rest periods
Department of Physiology and Pharmacology, West Virginia University, School of Medicine, Robert C. Byrd Health Sciences Center, PO Box 9229, Morgantown, WV 26506-9229, USA
Issue of Publication
Disease and Injury: Musculoskeletal Disorders of the Upper Extremities
Journal of Electromyography and Kinesiology
West Virginia University, Morgantown, West Virginia
Page last reviewed: April 9, 2021
Content source: National Institute for Occupational Safety and Health Education and Information Division