ABSTRACT
<p><b>OBJECTIVE</b>To illustrate the molecular mechanism of skeletal muscle growth by examining the effect of swimming training on skeletal muscle growth and p70s6k, rpS6 protein expression.</p><p><b>METHODS</b>Twenty four male SD rats were used to establish swimming training models with a 15% body mass load. The training protocol adopted interval swimming training (every other day with 8 weeks). The gastrocnemius and soleus muscle were collected and weighed after training, and the protein expression of p70s6k, rpS6 and their phosphorylated forms were examined.</p><p><b>RESULTS</b>After 8 weeks treatment, no significant change was observed in skeletal muscle mass between training group (T) and control group (C) (P > 0.05), but muscle mass in training rapamycin (TR) group has a significantly decrease compared with that in T and C groups (P < 0.05). Soleus and gastrocnemius muscle mass index in T group increased significantly compared with C group (P < 0.05). Compared with the C group, the ratio of P-p70s6k/p70s6k in T group increased with significant difference (P < 0.05), but the ratio in TR group was significantly reduced (P < 0.05). The ratio of P-rpS6/rpS6 had a significant difference between TR and T group (P < 0.05).</p><p><b>CONCLUSION</b>These results suggest that the interval training protocol is helpful to increase the relative muscle hypertrophy, and has a role in promoting the expression of p70s6k and rpS6.</p>