Why do bones crack?

Bone joint activity shows pop, mainly because joint muscle is in a certain posture for too long, usually lack of exercise, will show muscle strength imbalance, muscle chronic strain may also cause articular cartilage degeneration, joint fluid reduction, joint surface roughness, tendon may also show chronic aseptic inflammation and other performance, at this time bilateral joint activity asymmetry, joint surface friction increased will show pop. Commonly speaking, it is the sound of friction between joint surfaces, tendons, ligaments, joint capsules, muscles, etc., especially those who sit for a long time and work at a desk for a long time. The lubricant produced between joints is reduced, and the loss of joint friction is increased. It is easier to hear the sound of playing.