Butterfly stroke is a swimming stroke. 1953, FINA stipulated that breaststroke and butterfly should compete separately. After the separation of butterfly and breaststroke, butterfly became an independent event. In the early 1930s, in order to improve the speed of breaststroke, some athletes put their arms out of the water after paddling and extended their arms forward from the air like butterflies spreading their wings, so they were named butterfly stroke. At that time, this new swimming posture was often the same as breaststroke, which was collectively called prone swimming. Play games together. It was not until 1956 that butterfly and breaststroke were separated and competed as independent events in the Olympic Games. Since then, in order to quickly improve and improve the butterfly technique, the regulation that the legs can kick up and down in the vertical plane has been added to the butterfly rules, which provides a basis for the dolphin swimming variant of butterfly to participate in the official competition. Dolphin swimming is named after imitating the swimming movements of dolphins. Named after swimming movements. Dolphins have a half-moon tail fin. When they swim in, they use their trunks and tail fins to roll up and down to push their bodies forward and swim very fast. Dolphin swimming appeared long ago. In 1930s, American athletes made good achievements by using dolphin swimming technology, but they were not included in the competition because of the restrictions of the rules at that time. After the rules were revised, dolphin swimming replaced the original butterfly swimming in just a few years. 1957, Hungarian athlete G. Tumpek set a world record of 100 meter butterfly with a score of1'3 "4. In the history of competitive swimming, it can be said that swimming has never developed so smoothly and rapidly as dolphin swimming. The kick speed of butterfly stroke is the fastest in competitive swimming, and the stroke strength of both arms is also the biggest in competitive swimming. If its performance improves rapidly, it may replace freestyle and become the fastest swimming position in the world. But it has not surpassed freestyle so far, probably because its propulsion power is still uneven compared with freestyle. Paddling with both arms at the same time can produce great propulsion, but the speed drops rapidly when moving the arms. This uneven speed will inevitably consume more energy and affect the further improvement of sports performance. Since 1950s, the United States, Hungary, Japan, Australia, the German Democratic Republic, the Federal Republic of Germany, Sweden and other countries have made great achievements in butterfly swimming. In the world record, the men's 100 meter (54 "15) was created by Swedish athlete P Arveson, and the 200 meter (1'58" 21) was created by American athlete C beardsley. Women's 100 m (59 "26) and 200 m (2' 06" 37) are both held by American athlete mal. Butterflies in China developed rapidly in the early years. In the early 1960s, China ranked sixth in the world with the score of100m59 "1.