Muscle growth depends on the accumulation of long-term hard training. During training, various tissues and cells in the body consume a lot of energy substances, and these energy substances can only be gradually recovered after training by resting and supplementing nutrition so that anabolism exceeds catabolism. Recovery will exceed the original level in a certain period of time, resulting in the so-called "excessive recovery."

The amount of energy consumption and the speed of recovery are closely related to the intensity of muscle activity. In a certain range, the greater the amount of muscle activity, the more intense the consumption process and the more obvious the excessive recovery. The so-called "within a certain range" means that the amount of exercise should not be too large, otherwise the energy consumption will be too high and it will be difficult to recover. Overtraining for a long time will also lead to overtraining and even injury accidents. Only by mastering and applying the law of excessive recovery and observing the principle of gradual progress can muscles grow steadily.