The functional activities of limbs, including the movements of joints, bones and muscles, are all dominated by the liver and kidney.

Therefore, there is a saying that "the kidney governs the bones, and the bones are the rest of the kidneys". People who are good at health preservation should insist on physical exercise in winter to achieve the effects of nourishing and strengthening the kidneys, relaxing the muscles and activating the collaterals, smoothing the qi pulse and enhancing their own resistance, so as to achieve the purpose of strengthening the kidney.