Method We used biomechanical methods in controlling strain of anterior tibial muscles of rabbits .Objective To observe the histological and enzymohistochemical change after sprain.Result Experimental model of muscle sprain could be made with yield load which was about 128% of the body weight extracting anterior tibial muscle of the rabbits.Some of the muscle fibers broke near the junction between muscle and the tendon. Conclusion Fibrosis of endomysium and scar formation at the injury might be an important cause of frequent recurrence of muscle sprain.