When swimming, people usually use the buoyancy of water to lie prone or supine in the water, so that the whole body can be relaxed and stretched, so that the body can develop comprehensively, symmetrically and harmoniously, and the muscle lines can be smooth. Exercise in water reduces the impact of the ground on bones, reduces the probability of bone aging, and the joints are not easy to deform. The resistance of water can increase people's exercise intensity, but this kind of intensity is very soft, which is different from the equipment training on land. It is easy to control the training intensity in aerobic area, and it will not grow stiff muscle blocks, which can make the whole body lines smooth and beautiful.