Kinematics Analysis On Run-up And Take-Off Technique Of The 11^th National Games Men’s High Jump Athletes

By applying research methods such as literature data, photography shooting, video analysis, mathematical statistics method, this thesis makes a kinematics analysis on the run-up and take-off techniques of the top seven with a score higher than 2.20 m in the 11th National Games men high jump finals. The detailed results are as follows:1. Through research analysis, it has been found that there exists a significant difference between the last stride length of Chinese athletes and that of the world excellent athletes. Despite the relatively low proportion of stride length and height and smaller fluctuation of body gravity center of Chinese athletes, they take more time and show signs of interruption, thus affecting the connection of run-up and take-off.2. Horizontal velocity of body gravity of the last two strides in run-up stage of Chinese Fosbury flop is slower than that of world excellent athletes. The horizontal speed of body gravity of the last stride at the moment of starting slightly decreases compared with that of the last but two stride and significantly drops compared with that of horizontal velocity when leaving the ground.3. Inside gradient of all the seven athletes’the last but two stride slightly increases compared with that of the antepenultimate stride. And two of the seven athletes have smaller last stride inside gradient than the last but two, with Wang Chen reducing by 6.5° and Chen Ji 1.8°. This suggests that these two athletes slow down in the last stride of run-up, raise their body gravity center and lower vertical dynamic of take-off.4. The body gravity centers of Chinese athletes’ last three strides are slightly higher than those of foreign excellent athletes with greater fluctuation of body gravity center. The body gravity center of some athletes’last stride is higher than that of the last but two. The body center of Feng Xiaoming’s last stride is 0.1m higher than that of his last but two. As for Gao Wenbo, the number is 0.16m. The greater fluctuation of body center goes against maintaining speed and decreases energy transformation of take- off.5. The average touchdown angle when the takeoff leg landing in the take-off stage in the case of this thesis is 54.88°, with 57.13° of Feng Xiaoming as the largest angle and 52.76°of Chen Ji as the smallest one, while for the top one athlete Zhang Shufeng, that is 56.14°. By studying the video, it can be seen that Zhang’s whole set of movement is rather coherent, especially the connection of the last stride’s run up and take off. Under comparison, the connection of Chen Ji is reduced to be inferior.6. Loss rate of the taking off and stretching horizontal velocity at the moment of the take-off leg landing in the takeoff stage of Chinese athletes reaches 23.91% while that of world excellent athletes amounts to 36.73%. This difference results from muscle strength of athletes.7. The average angle of the knee joint when the takeoff leg reaching the biggest buffer in the take-off stage is up to 139.07° in the case of this thesis. Similarly, that of pelvis, knees and ankles in the take-off and stretch stage is relatively low and the driving of pelvis, knees and ankles are inadequate.Suggestions:1. In the run up training, athletes should strengthen curving approach velocity according to their actual conditions, set foot on the takeoff point actively and quickly through figuring out their own curving approach skills. Based on these, athletes should reinforce training of maintaining their speed in the last but two strides so as to break bottleneck in existing records.2. Athletes should continuously enhance their limb strength in training as a way to improve takeoff techniques. By finding out suitable ways in the takeoff training, they should control body center gravity’s height variation on the basis of increasing the horizontal velocity to achieve the best takeoff effect.3. Aiming at the inadequateness of taking off and stretching in the takeoff, special training on leg upholding should be emphasized in the training process and training on the coordination of pelvis, knees and ankles should be also enhanced.