Reinnervating rat skeletal muscle: effect of 35% grade treadmill exercise.

To determine the effect of 35% grade treadmill running on reinnervating rat skeletal muscle, adult rats were exercised for 1 hour on a 35% grade motorized treadmill, at a speed of 27m/min, once and twice daily, 5 days a week from the 3rd to the 6th week after sciatic nerve crush. Compared to the crush denervated control, the crush-denervated-twice exercised group decreased in the content of sarcoplasmic proteins (15.2%, p less than 0.05), and in the contraction time of the soleus (8.9% p less than 0.05). The percentage of type II fiber types in the plantaris increased 15% (p less than 0.05) in the once and 10% (p less than 0.05) in the twice daily exercised group. The findings of this study suggest that treadmill training performed during reinnervation did not cause muscle damage and may have increased the "fast" type muscle properties in the rat skeletal muscle.