ABSTRACT
<p><b>OBJECTIVE</b>To study the effect of exercises of different intensities on rat skeletal muscle cell apoptosis.</p><p><b>METHODS</b>Rat models of exhaustive exercise-induced skeletal muscle injury was established using tread mill exercises at different speeds, and the skeletal muscle cell apoptosis was detected using propidium iodide (PI) staining and flow cytometry.</p><p><b>RESULT</b>No obvious gastrocnemius cell apoptosis was observed in rats with normal exercise (P>0.05), but the cell apoptosis index was statistically significant in moderate and exhaustive exercise groups (P<0.05), reaching the highest level in exhaustive exercise group after exercising. The gastrocnemius cell apoptosis index increased obviously on days 1 and 3 of exercise, and stabilized in moderate and exhaustive exercise groups.</p><p><b>CONCLUSION</b>Exercises can evoke cell apoptosis and accelerate apoptotic cell clearance, and the imbalance between the two events during exercises may contribute to skeletal muscle injury.</p>