Acta physiologica Scandinavica
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New or increased muscular weakness, fatigue and muscle and joint pain with neuropathic electromyography (EMG) changes in a person with a confirmed history of polio constitute the cardinal symptoms of the post-polio syndrome. Unusual tiredness or fatigue is a common complaint in late polio subjects as is intolerance to cold. Fatigue in polio subjects can have several explanations: emotional fatigue, central nervous system fatigue, 'general' fatigue and/or neuromuscular fatigue. ⋯ Possible explanations may be an imperfection in the sarcoplasmatic reticulum with altered calcium release mechanisms (activation) or in sliding filament function (contractile properties). This may be a secondary effect to the enlarged muscle fibres. However, the prolonged subjective feeling of fatigue reported despite unchanged maximal voluntary contraction (MVC) remains unexplained.