When a patient has a bone ringing sound during leg practice, it is actually the patient’s knee joint ringing, because the patient’s leg practice requires frequent flexion and extension of the knee joint, which will cause the air bubbles in the knee joint to grow from small to large and gradually rupture, resulting in a ringing sound, which is a normal physiological ringing and does not require special treatment. If the patient has hyperplasia or degeneration of the bones and narrowing of the joint space, the cartilage in the joint will rub together when the patient practices the leg, which will also produce a ringing sound, but this is a pathological ringing sound, and the patient will have pain in the knee joint, which will affect the activity.