Joint rattling during exercise is mainly due to three reasons: first, it is due to degeneration of the joints, such as degeneration of the patellofemoral joint in the knee joint position, or wear and tear of the articular cartilage of the whole knee joint, with obvious foci of calcification and hyperplasia, or poor development of the patellofemoral joint leading to the emergence of a side of the grinding deviation, in the case of knee flexion and extension exercises, there may be a reset of the patellofemoral joint, or the bone The friction, irritation and extrusion between the structure and the bone structure may cause the rattling of the joint area. Secondly, it is due to the congenital development of the hip joint is not good, for example, the hip joint position acetabular dysplasia, relatively shallow, it causes the hip joint to present the state of subluxation, in the movement of the hip joint, it is possible to have a localized reset action, and there will be the sound of popping and rattling. Third, due to muscle soft tissue degeneration, resulting in decreased elasticity and toughness, due to excessive accumulation of local inflammatory lesions, resulting in muscle tissue degeneration, in the conduct of activities, will lead to muscles and ligaments and other soft tissues and the surrounding bony structures, resulting in more pronounced popping action, and therefore there will be a ringing sound.