To practice the strength of the quadriceps to do the following three things: 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 to maintain an upright position, can not lean forward, then the knees began to bend squat, the two toes of the direction of random can be. 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 80 ° flexion, if the patient is weak, weak thigh muscle strength, 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. If the practice of squatting horse stance when the knee joint does not feel pain is best, but some patients may have a painful angle when squatting, some squatting to 30 ° pain, some squatting to 60 °, or 40 ° pain. For those who will have painful angles when squatting the horse stance, it is best to avoid the painful angles when practicing. If squatting to 30° hurts, you can continue squatting down to 60° to avoid the 30° painful angle, and vice versa. If there is pain in any of the angles, the exercise should still be performed, just find yourself the least painful angle to practice. Because it is a static exercise, even if there is some pain, the wear and tear on the joints is minimal. The duration of a squat varies greatly from person to person, and is squatting until you can’t hold on. Rest for one minute between squats, and don’t rest too long. Then practice the second squat, and so on, for 30 consecutive minutes for the total time of a squat exercise that day, but some patients can consider the first week of practice, the total time of each exercise from 10 minutes, practice two to three weeks before the total time of each exercise will increase to 30 minutes, to avoid the beginning of the exercise, the knee will practice swelling or even pain. The number of exercises per day should also be decided according to your physical condition, 1-3 times per day is good. At the beginning, you can practice 1 time a day, each exercise for a total time of 10 minutes; later leg strength has grown significantly, their own muscles and joints adapt, and then increase to 3 times a day, each exercise for a total time of 30 minutes. Second, the special quadriceps medial head exercises: the knee joint in any position between 0 ~ 20 ° stationary, ankle hanging weights resistance exercises: the purpose is to practice in the squatting horse stance exercises are not easy to practice the quadriceps medial head (that is, the quadriceps most medial part of the muscle). The method is to hang weights on the feet sitting on the edge of the bed, the knee joint first completely taut, at this time the knee joint is at 0 °, and 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 an angle that does not hurt between 0° and 20°, stay still, and resist the weight hanging from the ankle joint. Guidance can not hold on before resting for half a minute to a minute. The weight hanging at the ankle joint to be able to hold on for 3-5 minutes at an angle of 0-20° at a time is good. If it is too light and you can’t feel it for 10 minutes, or if it is too heavy and you can’t hold it for 1 minute, it will not make the exercise satisfactory. Each time a certain angle of resistance exercises plus rest in between, the total time of all should be about 20 minutes – 30 minutes. If the duration of your knee joint squatting stance at about 80° of knee flexion can last 20 minutes in one breath, it means that your muscle strength is enough. 20 minutes is the standard that my teacher has been working out in the sports team since the beginning, so try not to lower the requirement casually. Otherwise the muscle strength is not enough to achieve the rehabilitation effect.