2. The blood supply of the whole body muscles is more abundant, and the total number of capillaries open to the outside world of the whole body muscles is greatly increased during fitness exercise, which can increase muscle fibers, make them thicker and enhance their ductility.

3. Bone joints are more plastic. Compared with adults, children's joint capsules and tendons are loose and lacking, and their firmness and reliability are correspondingly weak. Fitness exercises can enhance the energy of tendons.

4. Improve the blood supply capacity of the heart, the child's cardiovascular development is not complete, the expansion and contraction force is poor, and the blood supply belt is too small. Physical exercise can promote the development of cardiovascular system software and improve the coronary artery and blood circulation system of the body. The main manifestations are the bold font of myocardial tissue, the thickening of atrial wall, the increase of cardiovascular volume and the great improvement of blood supply capacity.

5. Logical thinking becomes dexterous. In the process of physical growth and development, the nervous system is the system software in the early stage of development. The successful completion of every posture in exercise requires the chemical reaction and manipulation of the central nervous system. In the process of operation, neurons can quickly reflect the agility, the degree of excitement and the whole adjustment process will be improved, and the stability and operational flexibility will also be improved. In other words, exercise promotes the development and perfection of the central nervous system.