Static (especially for patients with knee cartilage injuries)… To practice the strength of the quadriceps to do the following four aspects: a. Squatting horse stance: the purpose is to practice the strength of most muscle groups of the quadriceps. Posture with the Chinese martial arts in the crotch riding action or known as standing stance action, squatting horse stance. The patient’s legs apart, the distance between the two feet is slightly wider than the shoulders, the body remains upright position, can not lean forward, then the knees began to bend squat. The bending angle of both knees varies according to the patient’s physical condition and muscle strength. If the patient’s physical condition is good, good thigh muscle strength, squatting angle can reach 90 ° flexion, if the patient is weak, thigh muscle strength is weak, both knees can be lightly flexed, this time the half squat position is higher, the patient more effort, can be later with the exercise, thigh muscle strength increases, and then increase the angle of the knee flexion. Each patient will have a painful angle when squatting, some squatting to 30° pain, some squatting to 60°, or 40° pain. It is best to avoid the painful angle when practicing static squats. If squatting to 30° hurts, you can continue squatting down to 60° to avoid the 30° painful angle, and vice versa. The duration of a squat varies greatly from person to person, all squatting until they can’t hold on. Rest a minute between squats, do not rest too long. Then practice the second squat, and so on, for 30 minutes for the day’s squat exercise. Depending on your physical condition, decide how many times you want to practice. Practice 1-3 times a day. Second, the knee joint in any position between 0 ~ 20 ° stationary, ankle hanging weights resistance exercise: the purpose is to practice in the squatting horse stance exercise is not easy to practice the quadriceps medial head (that is, the quadriceps most medial part of the muscle). The method is to sit on the edge of the bed, the knee joint is first completely taut, at this time the knee joint is at 0 °, then slowly flex the knee, make it to flexion 20 °, and then slowly straighten to 0 °, which is the concept of 0 ° ~ 20 °. Repeat this several times to find a painless angle between 0° and 20°, staying still and resisting the weight hanging at the ankle joint. The weight hanging at the ankle joint is good to be able to hold in that position for 5 minutes. If it is too light and the activity is not felt for 10 minutes, or if it is too heavy and cannot be held for 1 minute, it will not make the practice satisfactory. Third, if the above two exercises have pain in any of the angles, each find an angle to practice the least pain. Because it is a static exercise, even if there is some pain, the wear and tear on the joints is insignificant. Fourth, the test method: if your knee joint in the bent knee about 80 ° squatting horse stance duration of a breath can last 20 minutes, it means that your muscle strength is enough.