1. When the human body reaches the age of 20, the qi and blood in the body begin to flourish gradually, and the muscles also grow and become strong, so this period is characterized by agility and brisk walking. People are at the age of 10~20 years old, which is the adolescence of life, which is what people call adolescence. This period refers to the transitional period when a person gradually develops from a child to an adult.

2. During adolescence, various organs of the body develop rapidly, and the functional activities of the internal organs and the circulation of meridians and qi and blood are relatively strong, which is a good period for human development.

3. Muscle bodybuilding needs high-intensity weight-bearing training. Although I started practicing at the age of 8, ordinary people still try less (preferably under the guidance of professionals). Under normal circumstances, after the completion of bone development, muscle development increases rapidly. Here comes the best effect.

4. Generally speaking, 16~24 years old is the most suitable period for muscle training, while the physical development of men starts from 16 years old, and the bones and muscles of 17 years old and 18 years old are not fully developed, so it is best to exercise after 20 years old.