Muscle Overuse Muscle overuse is a term used to refer to the condition which exists when workload demands exceed the physiological capacity of the neuromuscular system. The neuromuscular reserve in PPS patients will demonstrate marked variation, depending upon such factors as the extent of denervation at the acute onset of polio, the balance between ongoing denervation and reinnervation, and possibly the extent of cross-reinnervation. Clinically, weakness due to muscle overuse may be difficult to distinguish from weakness due to disuse. CK level abnormality is present in only about one-third of symptomatic individuals, therefore it can be considered as supportive evidence, only. MRI will show amount of muscle tissue in a limb, but will not indicate the cause of the condition of that muscle tissue.
Biopsy findings are equivocal.
Subjective findings, including data from activity diaries or information about occupational and domestic demands, may help to identify the workload demands on the neuromuscular system, its response to these and an indication as to which muscles may be receiving a given amount of use. Denervation hypertrophy is another means of adapting to challenge. Strength acquired through this process is limited, too. These muscles are at greater risk of developing overuse because their maximum ability to adapt to further physical challenge may have been reached. The presence of weakness in muscles with relatively large bellies is a sign of overuse, and may result in death of muscle fibers.