The thickness of a person's leg is determined by the muscle volume and fat of the leg. Muscle is made up of countless fibers. The main components of muscle fibers are fast muscle fibers and slow muscle fibers. Fast strength bodybuilding sports, such as sprinting and weightlifting, mainly involve fast muscle fibers, which can thicken the cross section of muscle fibers and make muscle groups developed and strong.
Endurance sports such as swimming, cycling and long-distance running mainly involve slow muscle fibers. Because there are abundant capillaries around slow muscle fibers, they have strong ability to oxidize fat and consume more fat when contracting. Therefore, often engaged in long-term endurance training, legs and body shape will become slender and symmetrical. Prevent the calf from losing its curvature and becoming like a straight stick.
Muscle is mainly composed of muscle tissue. Muscle cells are slender and fibrous, so muscle cells are usually called muscle fibers. In the theory of traditional Chinese medicine, muscle refers to human muscle tissue and subcutaneous adipose tissue.
Spleen governs muscles, and the nutrition of muscles comes from the transportation and transformation of spleen in Shui Gu. Muscle: name of anatomical structure. Therefore, the fullness of muscles is closely related to the rise and fall of temper. Su Wenping's theory of meteorology: "Dirty is really in the spleen, and the spleen stores muscle gas." Su Wen Wei Lun: "Spleen governs the body."
Reference: Baidu Encyclopedia Muscle