Kinematics Analysis Of The Last 5m Run-up And Takeoff Technique Of The First Eight Women's Long Jump Athletes In The 2018 National Athletic Championships

In the development of track and field sports and all kinds of large track and field competitions,the long jump project is not only loved by people because of its popularity and appreciation,but also plays an important role in improving people's explosive power and jumping ability.China's women's long jump project started relatively late,but through the hard exploration and efforts of Chinese researchers and coaches,the women's long jump has also made brilliant achievements,winning several Asian championships and breaking Asian records.At present,the Asian record is still set by Chinese athlete Yao Weili.Although our athletes have achieved excellent results in various competitions,there is still a certain gap between them and the world's elite athletes in the long jump.Therefore,researching the run-up and take-off techniques of elite female long-distance athletes in China,and comparing them with the world's top athletes in special techniques,which is helpful to discover the shortcomings and defects of Chinese athletes.At the same time,putting forward reasonable and effective suggestions is also benefit to make experts and scholars further understand the research and coaches more targeted training ? It is of great practical significance to improve the athletes' special skill level and improve the long jump technique gradually.This study takes the last 5m and take-off techniques of the women's long jump athletes in the 2018 National Track and Field Championship as the research object.The top eight athletes in the women's long jump finals are surveyed,using the literature method,on-site observation method,video analysis method,mathematicalstatistics method and comparative research methods and other research methods,analyze the research objects systematically and compare them with the world's top athletes,and draw the following conclusions:(1)In 2018 national track and field championships,the first eight women's long jump athletes showed a trend from big to small in the change of the final 5m step length in run-up,that is,the backward two steps were greater than the backward one,but the step length didn't change much,and the run-up rhythm tended to be consistent basically;In the change of run-up footwork frequency,only three athletes showed a rising trend,and their performance was reasonable.The run-up speed of the last 5meters was obviously lower than the world elite athletes,the run-up speed was slower;Pedal loss distance was relatively ideal,especially pan 0.10 m,which was close to the world's excellent level.(2)The average starting time of the top eight athletes in the National Athletics Championships in the 2018 National Championships was 0.118 s.Compared with the world's top athletes,there was no significant difference,and three athletes had a take-off time of 0.11 s,which is obviously better than some of the world's best athletes;The allocation of time in each period of time is unreasonable,that is,buffer time(T1)> stretch time(T3)> conversion time(T2).(3)The angle of knee joint of the top eight athletes in 2018 National track and Field Championship was larger,the maximum buffer angle is smaller,and the angle of pedal extension was also small at the moment of departure from the ground.Eight athletes landing pedal instantaneous hip movement was not obvious,not enough,take-off buffer stage hip extension range is small,there was a common phenomenon of hip flexion,which was not conducive to rapid pedal extension;The small hip angle from the ground was not conducive to the rapid movement of the athlete's body center of gravity,hindering the speed of the jumping leg;the athlete was relatively inferior in the flexibility and strength of the ankle,and the jumping was not sufficient.(4)The average landing angle of the first eight women in 2018 National track and Field Championship was 61.88 ±2.64 °,which was within the range of elite athletes.The average pedal angle was 71.81 ±3.53,which was within the range of theexcellent female athletes' stretch angle;The average value of the fan angle was 46.31± 3.50,which was significantly larger than the reasonable sector Angle range of Fairscher model.The landing Angle was relatively small,and the pushing Angle was relatively large,which lead to a relatively long displacement distance of the center of gravity of the athletes,resulting in a relatively large fan Angle.