Swimming is a sport, and it is a skill to float on the water by oneself and move forward in the water by the movement of one's limbs. Swimming can be divided into competitive swimming and practical swimming. Competitive swimming is the second largest event in the Olympic Games, including butterfly, backstroke, breaststroke, freestyle and synchronized swimming. Swimming modes that are of great value in military, production and life services are called practical swimming, such as crawl (freestyle), breaststroke, side stroke, diving, treading water (vertical stroke), water rescue, military swimming and backstroke. Swimming is one of the sports that men, women and children like. Ancient swimming, according to the existing historical data, is a consistent view at home and abroad, which originated from people living in rivers, lakes and seas in ancient times. In order to survive, they must catch waterfowl and fish as food in the water, and gradually learn to swim by observing and imitating the swimming movements of fish, frogs and other animals.