Exercise is produced by the contraction activity of muscles, which requires energy and oxygen. Muscle soreness after exercise is mainly divided into the following two situations: 1. After a long period of exercise or a short period of strenuous exercise, the blood supply is not sufficient, and the nutrients and energy required by the muscles for a short period of time are relatively high and cannot be replenished effectively. The muscle cells then carry out anaerobic metabolism, converting the glucose stored in the cells into lactic acid, while producing energy for exercise. The longer the exercise or the more strenuous the exercise, the more obvious the amount of lactic acid produced, so it makes people feel more sore. The more time is spent, the more oxygen and glucose is supplied to the blood, and the metabolism of lactic acid, the more sore muscles will improve. 2, too much exercise or improper exercise methods, and the resulting rhabdomyolysis, which produces creatine kinase, will also cause muscle soreness.