Effect of physical training on the proportion of slow‐twitch type I muscle fibers, a novel nonimmune‐mediated mechanism for muscle impairment in polymyositis or dermatomyositis

Abstract

Low muscle endurance in chronic polymyositis or dermatomyositis may be related to a low proportion of oxidative, slow-twitch type I fibers. Change in fiber type composition and increased muscle fiber area may contribute to improved muscle endurance and decreased muscle fatigue after a moderate physical training program.