Recovery of plantaris muscle from impaired physical mobility.

The purpose of this investigation was to describe and compare various methods of recovering atrophied fast-twitch skeletal muscle following long-term impaired physical mobility. An animal model was used to study morphological adaptations of atrophied plantaris muscles to the effects of 28 days of hindlimb suspension (HS) followed by either sedentary recovery or run training during a 28-day recovery period. Significant atrophy, demonstrated by decreased mean fiber area (MFA, micron 2), occurred during the 28-day period of HS. However, run training following long-term atrophy induced by HS did not result in the high levels of frank muscle damage and type IIC fibers previously reported in slow-twitch soleus muscle following long-term (28 days) atrophy.