Medicine and science in sports and exercise
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Med Sci Sports Exerc · Sep 2003
Athletes with exercise-associated fatigue have abnormally short muscle DNA telomeres.
Although the beneficial health effects of regular moderate exercise are well established, there is substantial evidence that the heavy training and racing carried out by endurance athletes can cause skeletal muscle damage. This damage is repaired by satellite cells that can undergo a finite number of cell divisions. In this study, we have compared a marker of skeletal muscle regeneration of athletes with exercise-associated chronic fatigue, a condition labeled the "fatigued athlete myopathic syndrome" (FAMS), with healthy asymptomatic age- and mileage-matched control endurance athletes. ⋯ These findings suggest that skeletal muscle from symptomatic athletes with FAMS show extensive regeneration which most probably results from more frequent bouts of satellite cell proliferation in response to recurrent training- and racing-induced muscle injury.