Behind the beautiful and thrilling somersaults, what factors affect the gymnasts' rotation?

In gymnastics competitions, athletes perform somersaults and twists in the air, which are thrilling and beautiful. What factors are at work behind these twists?

What events are included in gymnastics competitions?

In fact, gymnastics is a general term for a series of events. In addition to the competitive gymnastics, trampoline, and rhythmic gymnastics we see in the Olympics, there are actually many other events, such as single jump, skills, aerobics, parkour, including the currently popular children's cheerleading, etc., all of which belong to the general category of gymnastics, but these are non-Olympic events.

Competitive gymnastics, usually referred to as "gymnastics", includes six events for men: floor exercise, pommel horse, rings, vaulting horse, parallel bars, and horizontal bar, referred to as "freestyle, pommel horse, rings, vaulting horse, parallel bars, and single bar", and four individual events for women: vaulting horse, uneven bars, balance beam, and floor exercise, referred to as "high jump, flat jump, freestyle". The order of the abbreviations of this event is also the order of the competition. In team competitions or individual competitions, most of the time, male athletes compete in the order of "freestyle, pommel horse, rings, parallel bars, and single bar".

Gymnastics is a skill-based sport, and each individual event has its own unique charm and technical requirements. For example, in vaulting, athletes need to complete a series of movements, including running up, boarding, take-off, first jump, support, second jump, landing, etc., in a running distance of no more than 25 meters.

Gymnastics events have their own characteristics, but they also have one thing in common, that is, they all have rotations . There are two main types of rotations that athletes perform, one is a somersault and the other is a turn.

Somersaults refer to rotations around the horizontal axis of the human body, including one-turn somersaults, two-turn somersaults, and now there are up to three-turn somersaults. Rotations mainly rotate around the longitudinal axis of the human body, including 180 degrees half a circle, 360 degrees full circle, and up to four turns, that is, 1440 degrees.

Rotation

So, what are the factors that affect rotation?

One of the factors affecting rotation: physical fitness

First of all, physical fitness. Gymnastics is also known as the "father of sports". Because gymnastics has a long history, it is one of the earliest events to enter the Olympics. In addition, practicing gymnastics can improve our physical strength, speed, flexibility, coordination, balance, agility, etc., and can comprehensively exercise our physical fitness.

On the other hand, only those with a very comprehensive physical quality can become an excellent gymnast. Because as a gymnast, no matter what equipment you use to complete these difficult somersaults, you need strong leg strength, back and abdominal muscle strength, ankle strength and upper limb strength, and at the same time, you also need extremely high physical coordination and psychological quality.

In gymnastics choreography, the most difficult movements are usually placed at the front because this is when the athletes' physical fitness is the most abundant. As the competition progresses, their physical fitness will gradually decline, so they should try to show their most difficult movements at the beginning.

The second factor affecting rotation: mechanical factors

The second factor is the mechanical factor. The flips and turns in gymnastics are directly related to the athlete's run-up, take-off, and air time. Especially for the take-off, in normal training, the coach can judge whether the athlete can complete the action and the quality of the action by watching the athlete's take-off action.

To deeply study the nature of these forms of movement, we must consider mechanical factors and use the force of movement to study. Gymnastics movements include translation and rotation. Translation, such as running, and somersaults and turns, are rotations, involving concepts such as torque, angular velocity, moment of inertia, and conservation of angular momentum.

Torque is the tendency of an object to rotate around an axis or fulcrum, that is, a measure of the "turning", "twisting" or "bending" effect caused by the force on the object; angular velocity is used to describe the rotation of an object, indicating how many degrees it turns per unit time; the law of conservation of angular momentum is to ensure that the angular momentum of the body remains unchanged when the human body is moving in the air, or after the human body leaves the ground and leaves the equipment, the body is not affected by any external torque and is only affected by gravity.

Here, we will focus on the moment of inertia, because the moment of inertia is directly related to rotation. When a person or object moves, there is inertia, and the magnitude of inertia is related to the mass of the object or the human body. In rotation, there is also a physical concept of whether it is easy for an athlete to turn , which can be explained by the moment of inertia. The moment of inertia is related to the mass distribution of the object and the position of the rotation axis.

So how is the moment of inertia reflected in gymnastics?

To put it simply, when a human body jumps or leaves the equipment into the air, it is in a state of conservation of angular momentum. If the athlete's body relaxes at this time, the moment of inertia of angular momentum will increase and the rotation speed of the human body will decrease. Conversely, if the athlete holds himself tightly at this time, the moment of inertia of angular momentum will inevitably decrease, the angular velocity will increase, and the rotation will be faster.

When watching gymnastics competitions, we can see that when athletes do turns, they are basically in a state of full body tightening, and when they do tucks, their bodies curl up, and at this time, the moment of inertia decreases and the rotation speed increases. When athletes complete more rotations within a certain period of time, the moment of inertia increases, thereby slowing down the rotation speed.

The third factor affecting rotation: gymnastic equipment

The third influencing factor is gymnastics equipment. In competitive gymnastics, all sports need to be completed on equipment. In addition to the standard equipment used in training and competition, we also have other landing mats, protective mats, palm guards, and training auxiliary equipment. Only when athletes are proficient in using equipment can they complete various difficult movements.

With the continuous development of gymnastics training and science and technology, the style, height, and material of gymnastics equipment have been continuously improved in order to meet the needs of athletes to perform more complex and beautiful difficult movements, reduce the risk of injury, and reduce the psychological fear of athletes. The development of equipment, especially the use of some advanced elastic materials, has also laid the foundation for the development of gymnastics rules and gymnastics movements.

Particularly typical is the emergence of spring floor for free exercise, the increase in the height of the vaulting horse pedal and the area of ​​the supporting horse face, which has made possible a large number of difficult somersaults. The increase in the distance between the two bars of the uneven bar has provided great development for most of the movements of female athletes on the bar, and female athletes can perform movements that are no less than those of male athletes. In addition, the material and fixing method of the horizontal bar have also been improved, which has promoted the development of many flying movements, and athletes can complete a straight-body backflip with two turns of 720 in the competition, which is a very difficult movement.

The fourth factor affecting rotation: gymnastics clothing

Finally, another influencing factor is gymnastics clothing. Female gymnasts wear uniforms, basically the same clothing for the entire competition, while male gymnasts can wear shorts and go barefoot during floor exercises and vaulting.

Why is this?

Because floor exercises and vaulting horse mainly rely on the explosive power of the lower limbs, wearing shorts is more conducive to the athletes to complete the force and movements, and can hold the legs more firmly when tucked, making it easier to complete the movements. As for other events, which mainly rely on the upper limbs, wearing long pants can better reflect the athletes' fit body, as well as the elegance and beauty of the movements.

In gymnastics competitions, we can see many wonderful scenes, most of which are scenes of athletes successfully completing their movements.

But in fact, in gymnastics, somersaults and turns also have great risks. Behind these gorgeous movements, athletes take huge risks to complete them. According to our team's research, for the difficult somersaults in vaulting and floor exercises, when the body lands, the reaction force of the ground is about 15 times the body weight, which is a huge impact on the athlete's lower limbs. If the take-off is not good, the turn is not correct, and the timing of leaving the bar is wrong, it may bring very serious consequences.

Therefore, in the competitive gymnastics arena, behind every success lies tremendous effort and great risks.

Here I would like to share a short story with you. You may have seen the news that "Li Xiaoshuang died in one jump". What happened?

At the 1992 Barcelona Olympics, other countries' teams had finished their competitions, but our Chinese team had not yet won a gold medal in the gymnastics event, so the pressure fell on our athletes participating in the individual finals.

Before Li Xiaoshuang came on stage, the Japanese competitor had already completed a very high-quality move and received a high score of 9.787 points. This meant that Li Xiaoshuang had to get a score of 9.8 to win the championship. In this case, he decided to use a move that he had successfully and failed in his training, called the triple somersault .

It should be emphasized that few athletes can do this move now because it is too difficult. At that time, Li Xiaoshuang actually failed in training, and it was so serious that he had to be sent to the hospital for emergency treatment. At such a moment, the Chinese gymnasts showed their fighting spirit to complete such a difficult move. In the end, Li Xiaoshuang completed it with a very high quality and won the only gymnastics gold medal for the Chinese team in the Barcelona Olympics with a score of 9.925.

Planning and production

Author: He Wei, Associate Researcher at the Sports Training Research Center of the Institute of Sports Science of the General Administration of Sport of China, and Head of the Scientific Research Team of the National Gymnastics Team

Editor: Yang Yang