The functional activities of limbs, including the movements of joints, bones and muscles, are dominated by the liver and kidney, so there is a saying that "the kidney dominates the bone and the bone is the rest of the kidney". People who are good at keeping in good health should insist on physical exercise in winter to achieve the effects of nourishing tendons and strengthening kidneys, relaxing tendons and activating collaterals, smoothing qi pulse and enhancing their own resistance, so as to achieve the purpose of strengthening kidneys and strengthening bodies. ?