Although swimming is the same age as the Olympic Games, 85% of the 20 events set in the first three sessions were eliminated, which shows the great changes in swimming in the past 100 years. The early freestyle refers to the arbitrary posture of "eight immortals crossing the sea", but because of the fastest crawl speed, athletes all choose crawl without exception, so that freestyle has become synonymous with crawl. At the beginning of the 20th century, Cavell, who was born in an Australian swimming family, systematically reformed the simple folk dog crawling style. 1924 At the Paris Olympic Games, Weissmuler, an American athlete who later became a Hollywood star and an actor in Mount Tai, broke through the 1 minute mark for the first time in the 100-meter race, creating a standard crawl with two arms paddling alternately 1 time and two legs paddling six times. Breaststroke has undergone more changes. 1956 After the Melbourne Olympic Games, with the introduction of the new FINA rules, the final prosperity of diving breaststroke died with the waves, and the newly born butterfly stroke officially "broke through" from the branch of breaststroke and became independent, forming a stable pattern of swimming "four big families".
Why can't people sink in the water? In fact, the human body is 70% water, and the average density is between 0.96 and 1.05. Men and women, old people and children, fat people and thin people have slightly different body densities when exhaling and inhaling. An adult with a standard figure weighs about 3 kilograms when his head is above the water due to buoyancy. However, the resultant point of body buoyancy, that is, "floating center", is determined by the geometric center of each part of the body immersed in water and does not coincide with the center of gravity of the human body. The upper body is easy to float because of its small specific gravity, and the lower limbs are easy to sink because of its large specific gravity, which will produce torque. If you extend your arm horizontally above your head, the center of gravity and the center of gravity will be closer.
Why is the 100-meter dash much faster than the 100-meter swim? Because the motion mechanism on the ground and in water is completely different. Track and field athletes react by kicking the ground, and the distance that the soles of their feet "push away" the earth can be ignored. People who swim in the water have no fixed support, but can only push a certain mass of water to accelerate behind them and move forward with the help of reaction. Swing arm kicking is like a "propeller", which is an engine that produces thrust and lift. The basic principle of increasing horsepower is that the speed of paddling and pedaling should be as fast as possible, and the projected area of limbs in the direction of exertion should be as large as possible. Thorpe, an Australian swimmer, won five gold medals in two Olympic Games. He was born with a pair of big hands like cattail leaf fans and feet 47 yards long, which made him wear a pair of small hands and flippers. Phelps, an American swimmer who won six gold medals at the 2004 Athens Olympic Games, also took advantage of the advantages in water because he was born with big hands and big feet. In order to improve the efficiency of exertion and reduce the waste of physical strength, it is necessary to have correct and reasonable posture, hand shape, water angle and paddling route.