Research On Kinematics Of Chinese Excellent Female Athlete Luo Na Hammer Throw Technique

Technology is the core element of competitive ability in hammer throw.Excellent Chinese female hammer throwers repeatedly won MEDALS in the world competitions,which benefited from their ability to play their technical level well in the competition and convert their special ability level into competition results.This paper mainly adopts the methods of literature,questionnaire,video shooting,threedimensional kinematic analysis and mathematical statistics to carry out the kinematic analysis of the hammer throwing technique of the excellent female hammer throater Luo Na in the 2022 Chinese Athletic Association throwing Events Franchise Series(Huai’an Station,Jiangsu Province),and find out the key problems.In order to provide a realistic basis for the improvement and optimization of Luo Na’s hammer throw technique,and to improve the scientific level of our female hammer throw athletes’ performance and training.The following conclusions are drawn:(1)Through the expert letter consultation of Delphi method,the key technical indicators of the kinematic analysis of the hammer throwing technique of female hammer throvers are selected,including 5 first-level indicators and 20 second-level indicators,to provide theoretical reference for the future research and training of kinematics.(2)Time parameter: The time of each circle in the rotation stage of Luo Na hammer throwing technology is gradually shortened with the increase of the number of rotation laps,the time of second rotation,the time of final force,the total time of rotation and final force is shortened to get better results;The reduced double support time in the third and fourth laps of the spin phase leads to a better throw.(3)Speed parameter: In Luo Na’s hammer throwing technique,the acceleration rhythm of the hammer is stable,and the contribution rate of the ball speed is about 55% in the pre-swing stage.The acceleration rate of the ball speed increment of the four spins is ranked as the second round > the fourth round > the third round > the first round,which is more conducive to Luo Na to get a better result.The speed increment of the ball speed in the final exertion stage of Luo Na is too low,which influences the speed of the shot to some extent.It can be used as a breakthrough point for further improvement.(4)Angle parameters: in the rotation stage,the variation range of the shoulder chain Angle and the chain ball azimuth is small,and the technical stability is high,which is conducive to play a higher technical level;The left knee Angle and the torsional Angle of shoulder and hip changed greatly,the center of rotation fluctuated greatly,and the wrong technical movement of "back ball" appeared,which affected the effect of rotation acceleration.(5)Trajectory parameters: The trajectory length of four laps of Luo Na in the 6 throwing rotation stages of the race showed a trend of increasing from the first circle to the second circle and gradually decreasing from the second circle to the fourth circle.The inclination of track surface increases steadily with the increase of the number of turns,which is conducive to better race results.(6)In the6 throws of Luo Na in this match,the shooting speed is positively correlated with the throwing performance,and the shooting Angle and height are both in a reasonable range,with stable technical performance.According to the research results,the following suggestions are put forward:(1)Luo Na hammer throwing technique should shorten the total time of rotation and final force,gradually reduce the time of each turn in the rotation stage,actively accelerate the second turn in the rotation stage,and "land early" the right foot in the final force,which is helpful to improve the final force effect.(2)The speed rhythm of Luo Na’s hammer throwing technique should pay attention to the speed increment of the second and fourth laps in the rotation stage,and actively accelerate in the final force stage.This speed increment rhythm is more conducive to improving the performance of the competition.(3)Attention should be paid to maintaining stable acromial chain Angle,shoulder and hip torsion Angle and left knee Angle in Luo Na hammer throwing technique,steadily increasing the hammer rotation speed and improving the stability of technique.(4)The first two laps of Luo Na hammer throwing technique should actively extend the upper limbs,appropriately lean forward to increase the instantaneous radius of rotation and the length of the track.After the rotation stage,the radius of rotation can be lost appropriately,and the linear speed of the hammer can be improved by increasing the angular speed of rotation,so as to improve the speed of the hand.