Technical analysis of 20 17 long jump.
Abstract: The long jump technique includes four parts: run-up, take-off, flying and landing, which are organically linked to form the whole long jump technique. According to the different aerial techniques, the long jump technique can be divided into three postures: squatting, standing and walking.
First, run-up
Run-up, as an important part of long jump technique, is the way for athletes to gain forward motivation. Its main objectives are: first, to reach the maximum speed of flat running as much as possible at the end of the run-up; Secondly, in order to achieve the maximum running speed, we can pedal accurately to complete the take-off action and prepare for the best take-off effect.
(1) Run-up Speed
The purpose of athletes' high-speed run-up is to get the maximum take-off speed when taking off. Powell and Lewis' last 10m segmentation speed is very high, and the last 5m segmentation speed is faster than the previous 5m. At the end of the run-up, 10m reached the peak speed, and the run-up rhythm showed an increasing trend. According to Siruano's research, the long jump performance is highly dependent on the run-up speed (correlation coefficient R = 0.93~0.96). Popov's research pointed out that if you want to jump 8.5m ~8.6m, you must have a run-up speed of10.6m/s ~10.8m/s. Cao Xiaowen, Cheng Wancai and others found that every time the run-up speed is increased by 0. 1m/s, the performance can be improved by 0.08cm ~ 0. Zhao Guoxiong's research also believes that the run-up speed is more important than 70% among all the factors that affect the long jump performance.
(2) Run-up distance
In recent years, the run-up distance of the world's outstanding male long jumpers is 40-45 meters, about 22-24 steps, and that of women is 30-35 meters, about 17-20 steps. However, there is still a longer run-up distance. For example, the run-up distance of American Lewis is as high as 5 1.3m, which is related to his personal highest speed. With the constant changes of his special achievements, training level and absolute speed level, he will make necessary adjustments. Only a proper run-up distance can give full play to one's horizontal speed. If the distance is not long enough. You can't give full play to the speed level; If it is too long, it will result in ineffective physical exertion, and even the speed will drop when taking off. Therefore, it is the task of every athlete to determine the appropriate run-up distance in training.
(3) Run-up in the last few steps
Last four races of the run-up? There are three views on the 6-step run-up technique: the first view advocates the last 4? The sixth step should be smaller and faster, forming the rhythm law of run-up that quickly enters the take-off; The second view is that the last four steps of run-up should be two big steps and two small steps (especially the last two steps are the most obvious), which is considered to be the rhythm conducive to take-off; The third view is that when the step size is relatively stable, the step frequency is accelerated and the length of the last four steps has no obvious change. At present, elite athletes generally adopt the last technique, because increasing the step frequency is conducive to maintaining and exerting the highest speed, which makes the run-up and take-off closely linked.
Second, take off
Take-off is the most important link in the complete technique of long jump, which requires athletes to complete a series of take-off actions in the correct order under the premise of the highest run-up speed, so as to obtain the maximum initial take-off speed and appropriate take-off angle. With the development of take-off technology, take-off forms have gradually experienced passive take-off, braking take-off and impact take-off, and are generally considered to be more suitable until now? Running style? Take off. Practice has proved that this take-off technique can keep the horizontal speed well and create a larger take-off angle height in a short time. The whole take-off process consists of three parts: upper plate, buffer and pedal extension, each part has different mechanical characteristics and specific requirements.
(1) upper plate stage
The first is to put your feet on the upper board, which is the key to the combination of run-up and take-off. Run? Where to? Jump? The beginning of the transformation. The speed of the take-off action of stepping on the upper board directly affects the consumption of initial speed and horizontal speed, so the knee joint of the take-off leg in the last step of the run-up is raised low and needs to land actively. When landing on the ground, the heel and palm land almost at the same time, and the takeoff leg should have a proper landing angle. The landing angle of average elite athletes is (66? 3), because too large or too small will have a greater impact on the initial speed and take-off angle.
(2) Buffering stage
The function of cushioning is mainly to slow down the braking force of take-off, quickly change the movement direction of body center of gravity, and create favorable conditions for pedaling and stretching. The knee flexion buffer of the take-off leg makes the extensor of the take-off leg contract, improves the elastic potential energy of muscles and tendons, and increases the total contraction force of muscles. However, the statistics of elite athletes show that in order to achieve a good take-off effect, the knee joint should bend at least 65438+030, which creates favorable conditions for the future push and stretch. For example, the knee flexion of some elite athletes when landing is Lewis 165, the maximum flexion 140, Powell 17 1, and the maximum flexion 148. Smaller knee flexion angle can reduce the drop of body center of gravity during take-off, which is beneficial to support strength and ensure faster take-off.
(3) Launch stage
The research of Chupa et al. in the former Soviet Union shows that the body center of gravity is 3 ~ 8 on the vertical support surface at the time of maximum buffering, which is beneficial to improve the pedaling and stretching strength, and to help the take-off leg change from concession contraction to active contraction, thus obtaining greater pedaling and stretching impulse. Of course, the swing lever also plays an important role in pedaling and stretching. The purpose of pedaling and stretching is to fully straighten the three joints of hip, knee and ankle. With the increase of the range of activities, the upper limbs consciously swing forward and upward to lift shoulders and waist, which improves the center of gravity of the body. The function of swinging legs of lower limbs can not be ignored. At present, the running start has accelerated the speed of swinging legs, shortened the buffer time of take-off and accelerated the speed of pedaling and stretching. The amplitude of the swinging leg increases, which drives the hip joint to move quickly, which is beneficial to the full straightening of the take-off leg. Therefore, in the process of pedaling and stretching, we should make more reasonable use of the role of swing.
Third, vacate
Long jumpers can't change the parabolic trajectory of their body center of gravity after taking off. The purpose of aerial action is only to keep the balance in the air, make maximum use of this parabolic trajectory, strive for long range and prepare for a reasonable landing, that is, to minimize the loss of landing. Athletes will get different results by using squat, standing or walking long jump. In practice, now more and more people use walking long jump, because they know the walking action in the air in advance, so the swinging legs can cooperate efficiently and ensure a good take-off.
Compared with other jumping methods, the walking long jump technique is closely related to each technical part and has natural and coherent movements, which is convenient for the development of speed and the maintenance of air balance in the run-up. In addition, through the swing of arms and legs in the air, the trunk twists backwards, which is very important for good landing preparation.
Fourth, landing
Landing action has a direct impact on long jump performance. The task of landing is to make your feet stretch forward as far as possible, increase the distance between this position and the projection point of your body's center of gravity, prevent squatting and leaning back, and make your body move past the landing point and land safely. Before landing, lift your legs, stretch your legs forward, hook your toes and swing your arms back. When the heel touches the sand surface, press your feet forward and bend your knees quickly, move your hips forward and swing your arms back and forth to help your body move forward quickly and make your center of gravity move past the landing point as soon as possible. (Author: Graduate School of Beijing Sport University)
refer to
Li Hongjiang. Long jump [meter]. Beijing: People's Education Press, 1997.
[2] Yu Jun, Cao Jun. Multivariate regression analysis of the performance of outstanding male long jumpers at home and abroad [J]. Journal of Shenyang Institute of Physical Education, 2006:10103.
[3] Liu, Lin Sen-hua. Summary of research on the take-off speed of long jump [J]. journal of shanghai university of sport, 2000, (1): 59-62.
Jifeng Biomechanical analysis of long jump [J]. Journal of Jilin Institute of Education, 2009, (12):153-154.
[5] Li. Summary of Long Jump Technology Research [J]. Sports Research and Education, 20 1 1, (12):184-185.
Ding Wei, Liu Junhai, Cai Li etc. Summary of technical characteristics of modern long jump [J]. Journal of Physical Education College of Shanxi Normal University, 2004, (12):113, 174.
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