A Kinematic Analysis Of The Throwing Step And Final Exertion Technique Of The Outstanding Male Javelin Throwers In My Country

Study objective:The purpose of the study is to reveal the kinematics principles and laws of the throwing steps and the final exertion of the excellent male javelin athletes in China,and to summarize the factors affecting the performance of the athletes.Thus improve the javelin technical movements and sports performance in a targeted manner.Study methods: The literature method;three-dimensional video analysis method.Study results: It is not difficult to find that the difference between domestic and foreign male javelin athletes is mainly in the length of first step(lower than tthat of foreign athletes' 0.58m).the average length of the second step of the domestic athletes is 1.61 m,while the average length of the second step of foreign athletes is 1.84 m,the difference is 0.23 m.It can be seen from the data that the second step of domestic athletes generally adopts the throwing rhythm of small stride,which will result to insufficient javelin shooting time,and is not conducive to the stability of the subsequent process of controlling the javelin.The average value of length of crossstep of domestic athletes is 1.93 m,which is 0.26 m lower than the foreign athletes.It is not conducive to the formation of a good transcendence action before the final release.The rule fourth step of domestic athletes is similar to foreign javelin athletes,The step time of domestic athletes is 0.11 s smaller than the foreign athletes.At T1 and T2,the mean value of the trunk tilt angle of domestic athletes is relatively high;the trunk tilt angle has no difference at T3.At T4,the mean value of the trunk tilt angle of domestic athletes is 6.7° higher than the foreign athletes.The average speed loss rate from T3 to T4 of domestic athletes is 8.95%,and the height of the rise is much bigger.At T4,the mean value of the trunk tilt angle of domestic athletes is 2° higher than the foreign athletes,the mean value of the right knee angle of domestic athletes is 160.7°,which is higher than that of the foreign athletes.It indicates that the vacant high in the cross-step process increases the resistance in the landing process.At T5,the average value of the right knee angle of domestic athletes is 122.4°,indicating that the buffer is deep,which is not conducive to the strength of the right leg.At T7,the mean value of the left and right knees at home and abroad has no difference,from T7 to T10,the mean value of the left knee angle buffer amplitude of domestic athletes is higher than the foreign athletes' mean value 4.9°.Although the subsequent extension is better,it cannot reach the ideal value,which affects The final release height.At T10,the average angle of release of domestic athletes is 35.9°,slightly higher than the foreign athletes,and the angle of attack is larger than that of foreign excellent athletes,resulting in a large attitude angle of the javelin in the final release,which is not conducive to the continuous flight of the javelin,at the time of T7-T10,the mean value of the speed loss rate of domestic athletes is less than the foreign athletes,which is not conducive to the kinetic energy conversion between the human body speed and the javelin speed.The average release speed of domestic athletes at T10 is 27.52m/s,lower than the release speed of foreign excellent athletes(29.36m/s),indicates that the domestic javelin throwers have weaker ability to break out at the last release stage,which greatly affects the performance.Study conclusions: The difference of the step length between domestic athletes and foreign athletes is mainly in the rhythm of the first step.The average value of the trunk tilt angle domestic athletes at T1 and T2 is greater than the foreign average,and Zhu Kai's trunk is the most backward.The average speed loss rate from time T3 to time T4 is 8.95%,the speed loss rate is high,and the squat angle is high.At the time of T7-T9,the domestic javelin players' left knee angle buffer amplitude is reasonable.At T7 and T8,the mean value of the trunk tilt angle was 26.9° and 26.6°,both of which were slightly higher than the foreign athletes,and the degree of trunk tilt was reasonable.At T10,the average value of the release angle of domestic athletes is 35.9°,which is slightly higher than that of foreign excellent athletes,and the angle of attack is greater than the best angle of attack-3°,resulting in a larger attitude angle of the javelin in the final release.At T10,the average release speed of domestic athletes is 27.52m/s,which is 1.84m/s slower than the release speed outstanding foreign athletes(29.36m/s).