Exercise after knee ligament injury broadly includes two aspects, one is the exercise of muscle strength and the other is the exercise of knee flexion mobility. Whether the injury is to the anterior and posterior cruciate ligaments or the medial and lateral collateral ligaments, rehabilitation of the knee ligaments is very important and good rehabilitation can avoid stiffness in the knee joint. Knee muscle strength exercises, mainly active functional contraction of the quadriceps and hamstrings and knee flexion exercises. The flexion exercises are performed in 2-3 sets per day with the protection of a brace, with each set of 5-10 knee flexions, with a gradual flexion angle from 30 degrees to 120-140 degrees. In addition to this, ice, baking lamps and microwaves are given during the exercise to help eliminate swelling.