1, quadriceps isometric contraction training Objective: to enhance the muscle strength of the quadriceps. 1.1 straight leg elevation method patient supine position, knee joint straight ankle joint applied load (salt bag, sandbag, rice bag, etc. are available), asked the patient to straight leg elevation of the affected limb, leaving the bed 15cm, and asked to keep the limb position 5s feel muscle soreness leg down, so that the quadriceps muscle full rest, and then directly elevated according to the above requirements, repeated practice. Raise, put down for 1 time, 15 times for 1 group, practice 3 groups per day. Note: to lift fast and put down slowly. With the extension of exercise time, the load gradually increased to 2kg. 1.2 tense leg exercise knee as straight as possible, force the front of the thigh quadriceps muscle tense, ankle as far as possible dorsal extension, last 5s feel muscle soreness and then relax, tense, relax for 1 time, 15 times for 1 group, practice 3 groups per day. When exercising for the first time, the doctor will place his hand in front of the quadriceps muscle of the affected limb to feel the strength of the quadriceps contraction and assess the effectiveness of the exercise. 2.Quadriceps isotonic contraction training Purpose: To increase the range of motion of the knee joint. The patient sits on the backrest chair, the affected limb knee is quickly straightened, the ankle is dorsiflexed for 5s, then the knee is relaxed and slowly retracted, the knee is fully rested, and then the exercise is repeated as above. Straighten and retract count as 1 time, 15 times as 1 group, 3 groups per day. 3.myoelectric biofeedback therapy Patients take a sitting position, knee flexion 90 ° to the side of the bed, the feedback electrode will be placed on the affected side of the medial femoral muscle group surface. The positive stimulation level is placed close to the knee joint, the negative stimulation electrode is placed above the medial femoral muscle, and the ground level is placed between the positive and negative electrodes. The stimulation intensity was 20-100mA, pulse frequency was 2-100Hz; pulse duration was 2 seconds with an interval of 10 seconds; according to the prompt of the myoelectric biofeedback therapy instrument, the affected quadriceps muscle was contracted with force and the knee joint extension was completed as far as possible, and then slowly lowered according to the prompt. Gradually increase the amount of activity within the patient’s tolerance, tie 1-2 1kg sandbags at the affected ankle joint, treatment time 20 minutes, once a day, 6 days a week, 3 weeks for a course of treatment. 4. Knee isometric training method includes passive exercise and plyometric training. Passive exercise: isometric passive training of the knee joint at a speed of 600/s at the limit of flexion and extension for 10 min. plyometric training: isometric plyometric training of the movable range of the knee joint at 60°/s using the multi-joint isometric training system, 10 cycles for 1 group, 3 groups, 1 min rest between groups. 5. Health promotion: during the treatment of patients, health promotion should be done. Do health promotion such as obese people should reduce weight, wear sports shoes for shock absorption, minimize the load on the joint, avoid squatting, kneeling, kicking and other movements that increase the load on the knee joint. Patients should not walk or stand for long periods of time, use a bidet when using the toilet, use crutches to assist when walking in severe cases, and hold the stair handrail when going up and down stairs. When the limb is swollen, the affected limb should be elevated at rest, which is good for blood circulation and reduces the swelling of the limb.