Unloading or disuse rapidly results in skeletal muscle atrophy, switching to fast type fibers, and decreased resistance to fatigue. The recovery process is of major importance in rehabilitation for varies clinical conditions. Here we studied mouse soleus muscle during 60 days of reloading after 4 weeks of hindlimb suspension. Unloading produced significant atrophy of soleus muscle with decreased contractile force and fatigue resistance, accompanied by switches of myosin isoforms from IIa to IIx and IIb, and fast troponin T to more low molecular weight splice forms. The total mass, fiber size and contractile force of soleus muscle recovered to control levels after 15 days of reloading. However, the fatigue resistance showed a trend of worsening during this period with significant infiltration of inflammatory cells at days 3 and 7, indicating reloading injuries that were accompanied by active regeneration with up-regulations of filamin-C, alpha B-crystallin and desmin. The fatigue resistance partially recovered after 30 to 60 days of reloading. The expression of peroxisome proliferator-activated receptor coactivator 1 α (PGC-1α) and mitofusin-2 showed changes parallel to that of fatigue resistance after unloading and during reloading, suggesting a causal role of decreased mitochondrial function. Slow fiber contents in the soleus muscle were increased after 30-60 days of reloading to become significantly higher than the normal level, indicating a secondary adaption to compensate for the slow recovery of fatigue resistance.