There are three reasons why bones make sounds during exercise: first, it is similar to the snapping sound of fingers, which is the sound of closed joints being pulled open and the gas inside bursting (similar to the sound of bubbles bursting). The voice is crisp and single. A kind of hip and elbow joint, common at the root of thigh, is the sound of tendons and fascia sliding over the protruding parts of bones, similar to the sound of guitar plucking. The other is the noise generated by cartilage friction, which will be generated by the friction of the above tissues during exercise.