Exercise therapy Activities to avoid 1, try to avoid up and down stairs exercise, because up and down stairs for patellofemoral joint damage is greater. 2. Avoid walking on uneven ground, including the so-called “footpaths” paved with cobblestones. 3, avoid walking in high heels. 4, avoid prolonged standing, sitting and walking. Appropriate exercise therapy 1, quadriceps isometric contraction: we generally recommend that patients with the affected knee straight, the opposite knee flexion position (to avoid increasing the pressure on the lumbar spine), patients take the initiative to continue to tense thigh muscle training, at this time, the patient can touch the front thigh muscle significantly “harden”. Each tense thigh duration of 5-10 seconds, so repeatedly. 2.Straight leg raising exercise: leg raising can be done in supine position, side lying position and sitting position. The supine position is mostly used in the early post-traumatic period, and it is difficult for patients to perform sitting training. In order to avoid the influence of the iliopsoas muscle, the contralateral knee joint should take a flexed position when exercising in the supine position; the sitting position completely gets rid of the influence of the iliopsoas muscle. 3, progressive resistance exercise: a quadriceps straight leg raise exercise to enhance the way, that is, with the ankle joint attached to the weight, increase the load, in order to further enhance the muscle strength of the quadriceps muscle. Note that the following principles are used for exercise: heavy load less repetitions; medium load, more repetitions. General design position: now measure the maximum load (RM) for completing 10 repetitions and take that establishment as the base. Subsequent training is performed in three groups; the first group takes 1/2 the amount of RM and repeats 10 times. The second group, take 3/4 of the amount of RM, repeat 10 times, and the third group, take the full amount of RM, repeat 10 times. Rest 1 minute in between each set of exercises and perform once a day. Review the RM once a week to correct the actual load during the exercise and use it as a base for the next week’s exercise. 4. Terminal knee extension training: Terminal knee extension training is the knee extension exercise against the gravity of the limb within 30° of the flexed knee. 5. Swimming: The buoyancy of the water reduces the burden on the knee joint and the resistance of the water exercises the strength of the quadriceps. Knee flexion and extension in the water can significantly reduce the symptoms of osteoarthritis, and at the same time exercise cardiorespiratory function.