The hyperextension of the knee is mainly restrained and limited by the cruciate ligaments and the medial and lateral collateral ligaments of the knee joint. If there is no ligament disease, then the knee flexion exercises can be performed. The main purpose is to exercise the tendons and muscles on the back side of the knee, so that these structures are tight, thus correcting the knee hyperextension to a certain extent, generally choose the standing, weight-bearing, knee flexion movements, generally choose sandbags tied to the ankle, the weight should be light first, to prevent injury, after maintaining a standing posture, bend one knee close to 90 degrees, hold for 3-5 seconds, then resume standing, one side to do About 15 times, both sides are done to count a group, 8-10 groups per day.