The causes of knee pain in young people are mainly twofold: 1, due to strain accompanied by cold, such as excessive strain on the knee joint, too much flexion and extension activity, strenuous exercise, may lead to excessive fatigue of the muscles around the knee joint and other soft tissues, the formation of strain, especially in the case of warmth is not enough cold, it will lead to more muscle tension, blood circulation further decline, the resulting lactic acid and other metabolic products tend to accumulate, increase, on the peripheral nerve stimulation. 2, due to congenital joint development abnormalities, such as patellofemoral joint development abnormalities caused by patella grinding deviation, patella side of the cartilage wear is relatively large, easy to appear more obvious degeneration or hyperplasia, calcification, especially athletes who often carry out strenuous sports, it is easy to lead to local inflammation If there is a cold, it will lead to an increase in the accumulation of lesions, and obvious inflammatory edema will occur, which will stimulate the peripheral nerves to appear soreness and pain.