The knee joint is one of the most important weight-bearing joints in the human body, and it is often accidentally injured in life and sports. If reasonable functional training is not carried out in time after the injury, it often lays the hidden danger of dysfunction for normal life in the future. The following are some common methods for joint mobility after a knee injury. These methods are suitable for patients to practice at home, simple and practical, and can be used to help patients rebuild normal joint mobility. Knee extension: Knee extension is the most important basic function in my mind, even above flexion, because as long as the flexion angle is not less than 130°, basic daily life functions are not greatly affected, while the slight difference in extension is directly related to whether the bilateral limbs are functionally equal, and therefore whether the gait can be fully restored and whether normal power can be achieved. Therefore, it is important to pay close attention to the extension function of the knee joint. This is a way to practice straightening on your own. The affected limb is padded at the heel with a height of 10-15 cm, and a weight is pressed on the distal thigh (neither above the patella nor the proximal calf), the weight of which is appropriate to reach the limit of pain tolerance within 30 minutes. Generally 1-2 times a day as appropriate. This is also a way to practice straightening on their own, lying on the side of the bed, with soft pillows to knee pad up or empty outside the bed, hanging weights at the ankle, the rest of the requirements and the same as the above method, this method of calf self-weight force arm is longer, so stronger than the previous method of stimulation, especially relaxed, shall not be “stronger”. This is a method for others to assist in practicing the straightening function, the basic posture is similar to the first method, the helper stands on the side of the affected limb, hands pressed down on the distal thigh to strengthen the straightening angle, pay attention to the techniques must be used to prevent injury to their own wrist joints. This method should avoid violent pressure and still be implemented with gentle and lasting force. The basic posture is similar to the third method, with the helper standing on the side of the affected limb, pressing the fixed hip with one arm, holding the ankle of the affected limb with the other hand, and pulling it forward and downward in the direction of the black arrow, which can relieve the squeezing pressure on the subpatellar fatty tissue and synovial membrane when pressing for straightening, and relieve the pain in front of the patellar tendon. It is especially suitable for patients who have a “squeezing sensation” in front of the joint when practicing extension. If you feel that the patient is not fully relaxed or has a high tension in the N cord tendon before the exercise, you can make the patient do the N cord muscle maximum strength isometric resistance 2-3 times, this method can play a role in inhibiting antagonistic muscle tension and appropriate pulling.