The origin of high jump lies in the activities of ancient humans in overcoming vertical obstacles in life and work. As early as the Spring and Autumn and Warring States periods in China, "jumping high and leaping far" was used as a military skill in the selection and training of soldiers. Modern high jump originated in Europe. The earliest high jump poses were all freestyle, with athletes jumping over the crossbar with their own random movements. In the first professional track and field competition in 1827, the world men's high jump record was recorded as 1.575 meters, and in 1912, the world record first exceeded 2 meters. In the 1968 Olympics, Fosbury, a 21-year-old American college student, pioneered the "backflip" technique, jumping over 2.24 meters and winning the Olympic high jump gold medal, triggering another major technical revolution in the history of high jump. Each change in the development of high jump movements has more reasonably and scientifically exploited the potential of the human body. At present, all world-class high jump athletes adopt the backflip over the crossbar. Chinese athlete Zhu Jianhua set a world record of 2.39 meters in 1984. In 1993, the men's high jump world record had already reached 2.45 meters.
So what are the advantages of the backflip technique? The reason why people can jump up from the ground is full of mechanical principles. When jumping on the spot, people always first bend their knees and squat, lower their arms to increase the human body's pushing force against the ground. Then swing their arms upward and stretch their bodies. The harder they stretch, the greater the pushing force, and thus the greater the reaction force (upward push) on the human body from the ground. As long as this push force is greater than the human body's weight, the center of mass will gain upward acceleration, and the human body can leap up. When high jump athletes run quickly to the crossbar, they will quickly brake, reducing their horizontal velocity, resulting in knee flexion and vertical pushing off the ground, accompanied by a vigorous swing of their arms. Their knees, hips, and ankles almost simultaneously stretch rapidly, enabling the human body to gain a large upward acceleration. Once the body takes off, the center of mass of the human body will move along a certain parabola, which determines the size and direction of the jumping speed, and the maximum jumping height that the center of mass can reach is also determined. The movements of athletes in the air during the jumping phase are crucial for the height of the jump over the crossbar. From the changes of straddle, roll, and prone, the athletes' center of mass position over the crossbar is constantly lowered, thus enabling the continuous breaking of high jump records.
The backflip high jump created by Fosbury requires athletes to jump with their backs facing the crossbar and start with a single-leg takeoff, with their heads and shoulders passing over the crossbar first, and their bodies arching upward in a backflip posture before landing with both feet. The backflip technique enables athletes to jump over the crossbar at a height exceeding the maximum upward acceleration of their center of mass, thus constantly achieving new breakthroughs in high jump performance.
The technical characteristics of the backflip high jump are: the athlete's body forms an "arch" and a "back bridge" when passing over the crossbar, and various parts of the body "divide and conquer" the crossbar, unlike other high jump poses where the athlete's body passes over the crossbar in an instant. Of course, when adopting the backflip over the crossbar, athletes must master a skill very skillfully, that is, after the upper body passes over the crossbar, the upper body must be lifted up. Due to the conservation of angular momentum, the legs will also be lifted up almost simultaneously, so as to successfully pass over the crossbar without knocking it down.
During the process of jumping over the crossbar, part of the athlete's body is above the crossbar, and the other part is hanging below the crossbar. The overall center of mass position is outside the body and always below the crossbar, so there is an interesting phenomenon that the athlete's body passes over the crossbar while their center of mass passes under it. No wonder some people say that the backflip high jump is a high jump "drilled" under the crossbar. Other high jump poses all make the center of mass pass over the crossbar, while the backflip passes under it, so it naturally has an advantage and is sought after by athletes.