In sports competitions, diving is a very fascinating event. Athletes leap high into the air, soar, spin, tumble, and stretch before plunging into the water. This series of movements showcases the athletes' beautiful physiques in various free states and the graceful postures at the moment of entering the water. Since 1979, Chinese athletes have achieved excellent results in a series of major diving competitions, and are recognized alongside the United States, Russia, and Germany as the current world diving powerhouses. Modern competitive diving is divided into springboard diving and platform diving. The springboard is set at heights of 1 meter and 3 meters, while the platform diving heights are 5 meters, 7.5 meters, and 10 meters. As the platform height increases, the difficulty of the dives increases, with more complex movements and better viewing experience. However, we find that there are no platforms above 10 meters in international competitions, and this restriction is reasonable.
We often say "gentle as water", but as the speed of entering the water increases, water gradually loses its gentle side and reveals its "hard and cruel" ferocious side. Water is a liquid, and when an object enters the liquid surface, it needs to displace some liquid and occupy a certain space. In the process of "seizing" the liquid space, it takes time to displace the liquid. As the speed of entering the water increases, the time to displace the liquid becomes shorter, which inevitably results in a certain amount of resistance, and this resistance increases rapidly with the increase of speed. At 3-meter board diving, the impact force when entering the water is still very small and won't make people feel uncomfortable; at 10-meter diving, there is already a strong impact force, and people without professional training may be injured if the entry posture is incorrect; if it's a dive from a height of 10,000 meters, it's like falling onto a concrete surface, and people will die immediately. This phenomenon is scientifically known as "liquid hardening". In competitive sports, to protect athletes' personal safety, 10-meter height is the scientifically verified and practically proven extreme safety height. Diving from heights above 10 meters may cause varying degrees of harm to the human body. However, we often see diving movements far exceeding 10 meters in height, 20 meters or even hundreds of meters. This sport is called "high altitude diving". It's an extreme and thrilling sport. Divers can't enter the water with their heads first like high platform diving, but with their lower limbs first, otherwise it will cause skull fractures and lead to personal injuries. High altitude divers must undergo rigorous training to keep their bodies in perfect condition so as to cope with the huge impact force when colliding with the water surface. When divers contact the water surface, due to the huge impact force applied to their bodies, they often suffer from cramps and muscle spasms. Due to the harshness of this sport, high altitude divers can only jump up to 15 times a day, and after each jump, they must immediately receive muscle tissue massage.