Skeletal muscle reloading following disuse is characterized by profound oxidative damage. This study tested the hypothesis that intermittent hyperthermia during reloading attenuates oxidative damage and augments skeletal muscle regrowth following immobilization. [...] Heating resulted in ∼25% elevation in heat shock protein expression (P < 0.05) and an ∼30% greater soleus regrowth (P < 0.05) in RH compared with RC. Furthermore, oxidant damage was lower in the RH group compared with RC because nitrotyrosine and 4-hydroxy-2-nonenol were returned to near baseline when heating was combined with reloading. Reduced oxidant damage was independent of antioxidant enzymes (manganese superoxide dismutase, copper-zinc superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase). In summary, these data suggest that intermittent hyperthermia during reloading attenuates oxidative stress and improves the rate of skeletal muscle regrowth during reloading after immobilization. (via.)
The RH group was the group that got “reloaded” (had their hind legs weighted down to induce muscular growth) as well as received heat treatment, while the RC group didn’t get heat treatment. So if you read the abstract they’re saying that increasing that heat shock protein in those mice helped them rapidly regain the muscle they had lost from immobilization, and prevent the oxidative damage that muscles will characteristically experience after having gone through a period of disuse.