Technical characteristics of high jump
Most experts and coaches think that these two methods are advanced, and it is mainly based on the athlete's personal characteristics to decide what posture he adopts. One of the reasons why more and more athletes are unwilling to learn prone position is that fosbury flop is simpler and easier to master than prone position, and all kinds of athletes can jump. Even if the athlete's legs are not very long, or the flexibility of the swinging legs is poor, as long as the legs are strong and explosive, they can jump a very high height with the "back-style".
American athlete F. Jacobs is 1.73 meters tall, and the fosbury flop is 2.32 meters, which is 59 centimeters higher. However, Soviet athlete в Yashenkuang set a world record of 2.34 meters for outdoor high jump and 2.35 meters for indoor high jump. 1976, Olympic champion German * * and China female high jumper R. Ackerman became 1977 female athletes who reached 2 meters and won the championship title. They all jump on their stomachs. Although there are fewer and fewer athletes in prone position, the achievements made in this position are very high.
Prone technique
It can be divided into three parts: run-up, take-off, over-pole and landing. Athletes' approach angle is generally 30 ~ 50. The run-up distance of most athletes is shorter than that of fosbury flop, and the straight run-up is usually used for 6 ~ 9 times. In order to better prepare for the take-off, athletes lower their body center of gravity in the last four steps of the run-up, and at the same time, their feet are on the ground, and their stride length is larger and their stride frequency is slower than that of the fosbury flop. The penultimate step and "step" of run-up are the key points of run-up in prone high jump. In the penultimate step, the athlete's body center of gravity is lowered to the lowest position, with special emphasis on sending the pelvis forward. The forward speed of hip joint obviously exceeds that of chest. It is a feature of prone technique that the pelvis exceeds the chest when stepping. In the prone high jump, the take-off leg is close to the crossbar when stepping.
Pay attention to the straight leg swing when taking off. There are also a few athletes who bend their legs, swing their arms up, stand up and take off in the direction of the crossbar. After take-off, the athlete crosses the crossbar, with his body parallel to the crossbar and his upper body rotating in the direction of the take-off leg. When passing the pole, the whole body rotates along the longitudinal axis of the body, and at the same time, the take-off leg retracts inward to the chest, but the thigh should not be too close to the chest. When the calf is harvested at 90, the leg should be turned immediately, and the thigh should be turned outwards, so the hip joint needs to have good flexibility. Under normal circumstances, it is easy for athletes to knock off the beam at this time. After the whole body has crossed the crossbar, it is ready to land. When landing, you can support the ground with one hand or both hands, or you can land with both hands and swinging legs at the same time, and then land on your side.
Prone jumpers also use arc approach, and the circular inertia of arc approach is faster than that of pole vault. However, some people think that the straight run-up is better, because: (1) steps can run accurately; ② It's easier to play with speed. Prone high jump needs more strength, special strength and big muscle strength than fosbury flop. Because the athletes pass the pole at the same time, the swinging action of the swinging leg is much larger than that of backstroke, and the time of passing the pole is also shorter, so the prone jump method is more suitable for athletes with poor speed quality but good strength, flexibility and explosive force.
Back to back technique
It can also be divided into four parts: run-up, take-off, over-pole and landing. The run-up distance of backstroke is 9 ~ 1.2 step, and some of them are even longer. Run in a straight line first, and then run in an arc of 4 ~ 5 steps, which requires athletes to run fast and naturally, similar to sprinters' running methods. The last four steps of the run-up do not lower the center of gravity of the body, and the penultimate step adopts the foot landing. When stepping, you should also send your hips forward, but the amplitude is smaller than that of prone position, which is similar to the action of long jumpers taking off. Take-off is different from prone. Fosbury flop athletes should give full play to the horizontal speed of run-up, the explosive force of take-off and the swinging and bending of legs.
Generally speaking, the distance between the takeoff point and the crossbar is farther, and the distance between the takeoff point and the landing point is also farther. The biggest feature of the take-off of fosbury flop is that it must be rotated. The take-off leg is the leg away from the horizontal bar. When taking off, the swinging leg swings upward and outward, which makes the athlete make a rotation in the starting direction of the run-up. After taking off, turn back to the horizontal bar. Back-over-the-pole action is different from prone position. The athlete's body crosses the pole, and all parts of the body pass the pole in turn. When crossing the pole, the whole body is in an arc state on the pole, and the head, shoulders and chest are pressed down sharply behind the pole. When the body's center of gravity reaches the highest point, the thighs are down and the chest is out so as to cross the horizontal bar smoothly.
After the athlete's hip passed the pole, he began to land. In order to prevent the calf from falling off the crossbar, the athlete closes his abdomen and lowers his head, so that his thigh quickly leaves the crossbar and his calf is straight. Landing order: shoulder-arm-back-waist. The running method of backstroke approach is worth putting forward. At present, some athletes still have a high center of gravity until the last step, which is suitable for athletes with lighter weight, better speed and jumping ability, faster hips and steps, and thinner body. Such as Italian female high jumper S. Simoni and American male high jumper D. Si Tong.
The other method is similar to prone position, with the center of gravity obviously reduced in the last 4 ~ 5 steps of run-up, and the running stride is longer and the frequency is not as fast as the above method, which is suitable for athletes with average strength and not particularly fast speed, such as Polish male high jumper J. Vladjo and China female athlete Dazhen Zheng.
China high jump
Before the founding of the People's Republic of China, the level of high jump was very low. 1949 The national record of men's high jump was1.875m, and that of women was1.40m. After 1949, the high jump flourished and became one of the more popular events in track and field. The technical level of male and female high jumpers has improved rapidly. In the 1950s, many men jumped over 2 meters. The famous female athlete Zheng jumped1.77m with a score of 1957, surpassing the world record of1.76m held by American M. mcdaniel and Romanian I. ballas at that time. In the history of high jump, the world record was broken by the female athlete of China 1. In 1960s, the technical level of Chinese men's high jump also improved rapidly. In September, Ni from Quanzhou, Fujian Province broke the national men's high jump record for the first time with a score of 2.05 meters, with a score of 1960. 1962 ranked second in the world high jump with a score of 2.20 meters. 1965 ranked first in the world in men's high jump that year with a score of 2.25m, only 3 cm short of the world record. 1966, Ni won the gold medal at the Asian Emerging Power Games with a score of 2.27 meters. 1970165438+1On October 8th, in the track and field competition in Changsha, Hunan, he broke the world record of 2.28 meters held by the Soviet вн brumel with a score of 2.29 meters.
Although the high jump in China began in the first half of the 20th century, it developed slowly. After the founding of New China, the high jump developed rapidly. By 1956, the male and female high jump records reached 1.95m and 1.6 1m respectively. 1957, Zheng, an outstanding female athlete in China, broke the world record of1.76m with scissors high jump, becoming the first athlete in the history of track and field in China to set a new world record.
1970, Ni broke the world record of men's high jump with a score of 2.29 meters, which made China's high jump level leap again. At the same time, the women's high jump has made gratifying progress. 1965, five athletes from China entered the world before 10. At the end of 1970s, due to the introduction of fosbury flop, a number of outstanding high jumpers appeared in China, among which Zhu Jianhua was the most outstanding representative.
Zhu Jianhua, a native of Shanghai, China, is a famous high jumper in China and a former world record holder. Height1.93m, weight 70kg ... From1June 1983 to1June 1984, he broke the world record of men's high jump three times in a row, from 2.35m to 2.39m.. /kloc-at the age of 0/8, he flew over the height of 2.30 meters, breaking Ni's Asian men's high jump record of 2.29 meters, which was equivalent to the fifth place in the world that year. 1On September 22nd, 983, in the preliminaries of the 5th National Games, he broke the world record for the first time with a height of 2.37m. More than three months later, he broke the world record again with a score of 2.38m. In the same year, he won the high jump champion in the 5th Asian Athletics Championships and the third place in the 1st World Athletics Championships in Helsinki. World 1984 In the international high jump competition held in Eberstadt, the Federal Republic of Germany, he broke his own world record for the third time with an excellent score of 2.39 meters, and the overall level of China's high jump was further improved.
After the founding of the People's Republic of China, the technical level of high jump has improved so fast because of studying and studying advanced foreign experience, closely combining with China's sports practice, and gradually establishing training methods and various exercises suitable for the characteristics of Chinese high jumpers from the aspects of physical training, technical training, exercise amount arrangement and annual training arrangement. Under the guidance of bold exploration and following his own path, Zheng Zai 1956 began to implement the principle of high-intensity training. In 1957, while continuing to implement this principle, she increased her strength and adopted the most suitable and improved scissors technology, and her grades improved very quickly. 1955 ~ 1956 increased by16cm, and 1957 increased by16cm, thus breaking the world record. In the high jump training, Ni studied the characteristics of brumel, a Soviet athlete, gave full play to her own advantages, formed a unique technical style and achieved excellent results.
Abdominal high jump
Abdominal roll high jump mainly includes four steps: run-up, take-off, air posture and landing action:
run-up
Run-up is the exertion and control of speed. If the run-up speed is too fast, you will not be fully prepared for take-off, and you will lack a very huge leg strength to turn most of the horizontal momentum into vertical momentum; If the speed is too slow, it will not produce horizontal momentum, so the speed distribution is the unique essence of the high jump run-up. The roll-up approach is slightly forward, but it is changed to more upward speed, so the pace should be relaxed and elastic, the center of gravity of the body should take an arc, the heel should land, and it will spread to the soles of the feet and toes through the heel, and the ankle flexion and extension should be used more. Run-up has two main purposes: to generate horizontal speed, to change horizontal momentum into vertical momentum, and to be in the most helpful position for vertical landing when taking off. When the running speed is very slow, you can make a take-off angle of 45 degrees; The faster the speed, the less likely it is to keep 45 degrees. The larger the angle, the longer the takeoff distance, which affects the vertical speed.
1. Run-up speed: Run-up speed is determined by two factors: one is run-up distance, and the other is run-up time. The run-up distance 18m is about 9 ~ 1 1 step. The whole run-up can be divided into two stages. Step 1: Steps 5 to 7; The later stage is relatively short, 4 to 5 steps. When starting the run-up, you can start standing, or you can step on the starting line after walking or jogging for a few steps. The step number algorithm is based on the starting line. The standing start method is relatively stable, and the later running method can be buffered to avoid the initial tension. When running forward, the swinging leg should bend forward and swing forward, the supporting leg should be pushed back completely, the upper body should be kept forward, and the arms should swing back and forth with the movement of the legs. With the acceleration of run-up speed, the step size of run-up gradually increases; However, pay attention to the slight bounce.
After entering the back section, the body center of gravity cannot drop, and then the body center of gravity begins to drop in the last three steps. In order to effectively prepare for the take-off, the running action should be changed. The swinging leg lifts the thigh with the hip joint as the axis, and the knee joint of the thigh drives the calf to swing forward actively, and the calf takes off by its own impulse. The heel hits the ground first and quickly rolls to the front foot. Step on the rear pedal and keep your upper body upright or lean forward slightly. The two arms cooperate with the leg movements to increase the swing range back and forth.
Entering the first two steps of the take-off point is an important stage of the transition from run-up to take-off. At this time, the run-up speed also reached the fastest speed, and the body center of gravity also fell to the lowest point. After this stage, the maximum run-up speed and the height of the center of gravity are continuously input to take off. In the last step, the body should lean back and the hip position should be lowered, so that the high jumper can effectively and quickly change the horizontal momentum into the vertical momentum, thus producing the most favorable pre-take-off posture. The last step is about 20 ~ 30 cm shorter than the second step, and its action focuses on energy storage rather than the speed of production. So the last step should be to reduce the vibration and increase the working distance. If the three joints of hip, knee and ankle are still straight at this time, the extensor muscles of lower limbs have no room for contraction, so they must flex, but the degree of flexion is not great. If you bend over greatly, your body's center of gravity will sink excessively, and at the same time, your legs will move in circles from flexion, which is time-consuming and reduces the upward speed, affecting the jumping height.
2. Run-up direction: The belly-rolling start adopts the oblique running direction, and the angle formed by the oblique running run-up and the horizontal bar can be large or small, depending on personal speed habits. The run-up direction may have a great influence on the partial rotation during take-off and the proportion around vertical, horizontal-horizontal and intermediate-horizontal axes. In fact, the run-up action is a jumper's take-off, which is a continuous action in the air, so once the habit is formed, any drastic change in the direction of take-off will inevitably hinder the performance. The oblique run-up is beneficial to the high jump and can increase the active surface of the swing when taking off. Before the center of gravity reaches a high point, it is possible to throw some parts of the body above or below the pole. However, if the run-up slope is too small, the high jumper will bump into the crossbar, regardless of whether he crosses or not, he will bump into the crossbar at any point in the higher position. Secondly, the inversion should be completed at the time of take-off, expanding the inclination to the horizontal bar and reducing the effective elasticity. Generally, the run-up angle of about 30 ~ 40 degrees is appropriate.
3. Measurement of run-up point: First, we should know the number of run-up steps, then determine the stride length, and then determine the distance and direction of run-up. The measurement of step points can run at an inclination of 30 ~ 40 degrees from the jumping point and run in the opposite direction. In the last step, take the falling point of the vault as the starting point of the run-up, and then run several times from this starting point to the jumping point to make corrections. If you practice on the red brick powder or cinder track, you can correct it with spikes, which is very convenient. After the running point is stable, it can be measured by walking, ruler length or tape measure, and the angle and direction must be considered when measuring, which is convenient for future application.
take off
Take-off is the key to determine the height, which is to change the horizontal momentum into vertical momentum, leaving only a part of the horizontal momentum across the beam. From the mechanical principle, take-off is the upward resultant force generated by the forward force and the obtained reaction force when the take-off leg is propped forward. So the jump angle is large. Take-off is the action from the last step of the run-up to the moment when the take-off leg takes off from the ground when the swing leg is supported vertically.
1. Landing of take-off leg: from the last step of the run-up supported vertically by the swinging leg to the time when the whole foot of the take-off foot is supported. In the last step of the run-up, swing your leg forward, follow the ground with your feet, and quickly roll to your toes. At the same time, the pelvis moves forward quickly, and when it reaches the vertical part of the support, the center of gravity of the body drops to the minimum, and the knee joint flexes to the maximum, so that the flexors and extensors of the knee joint contract more, and the elasticity naturally stores energy, which is beneficial to the vertical upward movement of the center of gravity. When the pelvis moves forward through the vertical part of the support, the swinging leg begins to push the ground quickly and forcefully, so that the pelvis moves forward and upward beyond the shoulder. The take-off leg bends forward at the same time, drives the thigh with the hip joint, then stretches the calf, and the heel moves forward along the ground. When the body center of gravity has moved up, they quickly step out of the take-off point with their feet and quickly transition to full sole support, which reduces the braking effect of the take-off leg and accelerates the forward and upward movement of the body center of gravity. The swinging leg and two arms should be coordinated with the take-off leg. After the swinging leg is pushed back quickly and forcefully, the take-off leg stretches forward and starts swinging when it is about to land but not yet. At this time, the pelvis moves forward quickly, and the swinging leg stays behind as much as possible, fully lengthening the flexion muscles of the hip joint, which is beneficial to swing forward quickly and greatly. As the take-off leg is placed at the take-off point, the pelvis moves forward and upward, and at the same time completes the movement around the horizontal axis, accelerating the swinging leg to swing forward under the drive of the pelvis. In the last step, when swinging the leg as a take-off leg, keep the upper body upright or slightly lean forward. As the swinging leg completes rolling, the take-off leg moves to the take-off point, and both arms pull back and swing forward and upward at the same time. 2. The take-off leg supports the top: the take-off leg supports the whole foot until the knee joint bends to the minimum angle. Due to the fast run-up and the moment of inertia of the swinging leg, the knee joint of the take-off leg is forced to bend, buffering huge momentum, and the whole body is like a compressed spring, storing huge energy and forming a "shape". At this time, the hip joint should be kept straight, the center of gravity of the body should move up gradually, and the swinging leg should continue to drive the thigh to swing forward with the hip joint. When the knee swings over the take-off leg, the toe lifts upward to push and pull the calf quickly, and swings vertically forward and upward. When placing and stretching the calf, the angular velocity and moment of inertia are weighed to increase the angular momentum, and the upward instantaneous force is increased by using this angular momentum.
3. Kick-off: In order to make the body rotate through the pole in the air, the whole body of the take-off leg should be slightly inclined to the horizontal pole during the kick-off, so that the center of gravity of the body deviates from the line of action of the kick-off reaction. Swing leg The straight leg swings forward and upward, and at the same time brings out the hip on the same side; Turn your body slightly to the beam. When the two arms swing, the shoulder on the same side of the swing leg is slightly higher than the shoulder on the side of the take-off leg, resulting in instantaneous rotation force of the body around the sagittal axis and the longitudinal axis, which makes the body change from a vertical posture to a horizontal posture after take-off, and lie on the horizontal pole with a lower center of gravity and cross the pole around the longitudinal axis.
Air attitude
After take-off, the body rises upward, although it has no force to improve the center of gravity, but it has a great relationship with changing the flight trajectory of the center of gravity. Although the height of the body's center of gravity is the same, the result of passing the pole is quite different because of the different air posture.
Once the take-off body enters the air, the body loses its support, and the movement without the center of gravity cannot change the flight trajectory of the center of gravity of the body, and the body still has to move along the projection line determined during the take-off. In the air, all the angular momentum of jump shot rotates around the momentum axis, which is beneficial to the control of rotation and balance, and is especially useful for the preparation of landing. If a part of an object moves to one side of the rotating shaft in the air, it will inevitably move in the opposite direction on the other side of the rotating shaft.
1. Turn over: The best posture for passing the pole is that the center of gravity is still on the pole. The reverse action is to make the upper part of the rod move downward by keeping the center of gravity unchanged, resulting in the reaction force that the lower part of the rod passes over the rod. The higher the weight of the high jumper on the pole, the higher the body posture and the worse the handstand action. On the contrary, when the high jumper is at the highest point, the weight under the pole is larger, and the closer he is to the ground, the better his handstand action will be, because all parts of his body are obviously over the crossbar. The belly-rolling inverted solid takes the longitudinal axis as the center of gravity axis and rotates around the longitudinal axis. At the highest point in the air, the jumper's head, upper body, arms and legs are relatively low, which is economical and labor-saving.
2. Action in the air: the centrifugal landing of the take-off leg produces take-off rotation, which is then converted into angular momentum of the swinging leg arm; The rotation around the horizontal axis in the air is obvious, and the rotation around the vertical axis will also occur. These two rotations are both in the direction of the horizontal pole, and the rotation around the horizontal axis is a different form of rotation. In some belly rolls, the angular momentum generated by the swinging leg is greater than the compensation momentum of the forward rotation of the take-off leg around the take-off leg, so the take-off leg leaves the ground with a backward rotation around the horizontal axis, or does not rotate at all. The momentum direction of the belly roll forms an angle of about 30 ~ 40 degrees with the crossbar, and slightly inclines to the bunker. Therefore, in the whole take-off process, the momentum axis of high jumpers is at an obvious angle with the longitudinal axis. That is to say, after the belly roll take-off, the take-off leg is temporarily suspended, and the hips remain high, which helps the swinging leg to rotate around the crossbar quickly, and then generates a reaction force to move the trunk, so that the trunk is closer to the momentum axis. Swing your legs back into a posture parallel to the crossbar, so that you can get speed by rotating and reversing. The head and chest can only pass the height of the pole and immediately fall under the spindle, while the legs and legs are relatively raised. The posture of rotating belly after exceeding the height of momentum axis is a high jump mode based on human body structure. The normal posture is to tuck in the abdomen and bend the hip. In the range of pelvis and hip joint, it is easy to change posture forward, the angle changes greatly, and the action is natural, so it is easier to cross the pole.
Landing action
Landing action is to consider the landing site, landing with larger body parts, or landing with flexible limbs to increase landing time and absorb strength, so that the body can land safely. In the past, the belly roll landing landed at four points in turn: right hand, right shoulder, back and right foot. The segmented motion of the joint is used to gradually buffer the ground force, but the rod is turned to the ground.