Fitness is nothing more than making muscles more developed. The overall thickness of muscle is an important criterion to measure muscle strength and muscle development. Only when the number of muscle fibers in the muscle increases, the muscle fibers are strong and the physiological cross section of the whole muscle is large can the muscle develop. The principle of muscle growth is actually excessive recovery. After muscle fiber injury, it will be lower than the original level for a while, then exceed the original level, and finally return to normal. Destroy the muscle, give it better nutrition and rest, and make it stronger again.

Therefore, it is very important to supplement nutrition and energy at ordinary times. There is no need to gain weight, and gaining weight is also fat, which can only be used after being decomposed into energy. Besides energy, the most important thing for long muscles is protein's supplement. It is recommended to eat more high-protein food, and beef is the best meat.