ABSTRACT
The experiment was designed to simulate active training with animal model. A dynamic and static trai-ning program for adult rats was carried out 30-60'/day, lasted from 25 to 232 days. The rats were killedperiodical1y in batches and the sections were prepared for exploring histological changes in knee and ankle areas on L/M. Degenerative cbanges in quadriceps and gastrocanemius muscles appeated by degrees aftet a period of in-tensive training. The nuclei proliferated in chains or clusters arranged in the center and the edge of thefibers. The number of nuclei for each chain or cluster could be as much as 20 or 30. Meanwhile, therewere also ischemic changes in small vessels. All these were the characteristic changes induced by mictotraumain muscles under repeated active and strenous training. In calcaneal and patellar ateas, there were changes of cartilaginous degeneration, necrosis and prolifera-tion (cartilaginous exostoses and osteophytes) too. The typical changes of enthesiopatby---degeneration, necrosis and proliferation (osteophyte) could beobserved in calcaneal tendon and its insertion area and in superior insertion atea of lower patella. The occur-rence of enthesiopathy in this experiment migbt be related to tke stress of traction force within muscle andcartilage during running in upward treadmill.