The Kinematics Analysis Of Feng Jie's Rotary Shot Put Technique

Research purposes: This study took the example of Feng Jie,a sportsman who won the bronze medal in men's shot at the 13 th National Games.The study purpose is to diagnose the special strength training method and discover the technical deficiencies.The strengthening and improvement of individual technical movements of Feng Jie provide kinematics theoretical basis,and at the same time,it also provides certain theoretical support for the similar research methods and the Chinese shot put teaching and scientific training.Research method: Using literature data method and APAS video analysis software analyzed the athlete's(Feng Jie)technical action video,using the low pass digital filter method smoothly handled the original data first,the cutoff frequency is 8 Hz,using Dartifish as auxiliary analytical software analyzed some data and then using mathematical statistics calculated and analyzed the paper.Research result:1.In the double-support phase:Feng Jie's total exertion time is relatively long;the left and right knee,hip,and shoulder angles are controlled within a reasonable range.2.In the single-support stage: Feng Jie spent a relatively long time,and his left leg was actively preparing for the rapid departure from the ground.The characteristics of changes in the angular velocity of the left and right knee joint,hip joint,and shoulder joint are: when the degree of the left knee angle is between 100°-160°,the degree of the right knee angle 120°-165°,achievement is ideal.The left knee angle speed is normal;the value of the angular velocity of the right shoulder joint is smaller than that of the right hip;the time spent in the single-support phase is longer,which is not conducive to the acceleration of the rotation at the later stage and quickly enters the emptying stage.3.In the emptying stage: Feng Jie's time for completing the technical movements at this stage varies in length.The characteristics of changes in the left and right knee joints,hip joints,and shoulder joint angles is that the right knee angle is larger than the left knee and the right leg is twisted.At the end of the time,there was a significant negative correlation between the hip joint angle and the performance.The decline trend of the right hip joint angle was not obvious;the right shoulder joint angle was larger than the left joint angle.4.In the transitional phase: the transitional phase is basically the same in proportion with little difference;from the perspective of the changes in the angles of the left and right knee joints,hip joints,and shoulder joints,it can be concluded that Feng Jie's coherence of technical movements,vacant and final exertion phase is convergence better during this phase.5.At the final exertion stage: the final exertion time was too long and the lower limbs did not actively stretch.The characteristics of changes in left and right knee joints,hip joints and shoulderjoints is that their angles control within a reasonable range from the left and right knee joints,which is consistent with the technical principle of rotating shot put.There was a negative correlation between the score of the shot and the left hip angle at the end time and the maximum moment,and a positive correlation with the right hip angle.With the improvement of performance,the left shoulder angle and the right shoulder angle all show an upward trend at the maximum moment,and the right shoulder angle is larger than the left shoulder angle.Feng Jie's physical center of gravity,gravity speed,shot-putting speed,shot angle,shot height,and shot speed are different from those of elite athletes in the world.The center of gravity is low,and the speed is too early.The difference between shot speed and body center speed is small.Muscle explosiveness is insufficient.Analysis conclusion:1.During the single-support phase and the final exertion phase,Feng Jie spent too much time.The right knee joint,the right hip,and the right shoulder had reasonable joint angular velocities,and in the final exertion phase,the right shoulder was supposed to have a higher rotational speed than the left and right hips.This will be conducive to the best shot speed and shot speed in the later period,which is the most critical part of the rotating technology.2.In the final exertion stage,Feng Jie's body center of gravity speed dropped too much,there are features of premature acceleration of the right hip and right shoulder,the overall movement speed is less positive,the ability to continue accelerating the ball is poor,indicating that the force action is unreasonable.In spite of the fact that the mechanics of breaking the link are faster,the speed of the final shot is less than the speed of the world's top athletes.The other sports techniques are performed at the last moment.These technical indicators are limited by the athlete's own conditions and fail to meet the targets of the world's best athletes level.