After ACL reconstruction surgery, there is a long period of inactivity of the knee because the ligament has to heal. Over time, the muscles between the thighs will become adherent, and during knee bending activities, the main purpose is to make the adherent muscles separate again, and this process is very obvious pain, which is a very common phenomenon in the early stage of functional rehabilitation exercises. Even in this case, the functional rehabilitation should be carried out in a gradual manner, the later the exercise rehabilitation, the better, the appearance of pain will be less and less. Only in this way can the strength of the entire thigh muscles be restored, and the range of motion of the knee joint can be restored, so as to prepare for the future to go down to the ground accordingly. Otherwise, if the functional rehabilitation exercise is not good, the restricted range of motion of the knee joint will cause weakness of the lower limbs, and even affect the normal daily life. Early exercise, the pain is really unbearable, you can go to the rehabilitation department of the hospital, treatment and exercise at the same time.