The purpose of this study was to determine the effect of exercise training on the length and circumference of atrophied muscles to see whether improvement in restoring the atrophied muscle mass, of either length or circumference growth could be induced through exercise training. Adult female Wistar rats were maintained for 14 days with hindlimb suspension. Rats were then assigned randomly to a sedentary group or training group. The length and circumference of both atrophied soleus and plantaris muscle for the training and sedentary groups following hindlimb suspension were compared with those of a control group. Length and circumference of both atrophied soleus and plantaris muscle in trained group was compared with those in the sedentary group. The results can be summarized as follows ; 1) Atrophy of soleus and plantaris muscle was induced with hindlimb suspension. 2) The circumference of both the soleus and plantaris muscle following hindlimb suspension was reduced to 51. 72%, 66.67% respectively compared to the control group. The length of both the soleus and plantaris muscle following hindlimb suspension did not show any difference compared to the control group. 3) There was no difference in length for either the atrophied soleus or plantaris muscle between the trained and the sedentary group during recovery from hindlimb suspension. 4) The circumference of both the atrophied soleus and plantaris muscle did not return to normal in the sedentary group, however, the circumference of both the atrophied soleus and plantaris muscle were significantly greater than of the control in the trained group, 14.22% and 9.38% respectively. 5) The circumference of both the atrophied soleus and plantaris muscle in the trained group was significantly larger than that of both muscles in the sedentary group at day 28 of recovery. From these results, it can be suggested that improvement in restoring the atrophied muscle mass through exercise training might be induced by growth of the muscle circumference.