Three-Dimensional Kinematics Research On Throwing Technique Of The Women's Hammer Gold,Silver And Bronze Medallists In Tianjin National Games

The complete throwing technique not only requires the hammer player to achieve the "man-ball" coherence and coordination acceleration,but also requires the hammer player to overcome the strong centrifugal force produced in the process of rotation.In the case of maximum rotation radius,the hammer player plays as fast as possible in order to get the fastest initial shot speed and throw farther.In this study,gold and silver in the final of the women's hammer event of the 13 th National Games of the people's Republic of China were held in Tianjin on September 6,2017.Bronze medalist achieved the best results in throwing the ball for the research object.< preparation of Zhang Wenxiu,the national team of the track and field hammer event of the State Administration of physical Education Tokyo Olympic Games(2017)Integrated Science and Technology Service > the research group used star-high titanium three-dimensional motion analysis system for Tianjin National Games gold,silver,bronze medal winners of the best performance of the hammer technology movement image kinematics analysis,Taking the three-dimensional kinematic parameters of the special technique as the main research content,this paper makes a quantitative technical diagnosis on the throwing technique of the elite female hammer players in our country,and tries to explore the three-dimensional kinematic characteristics of the gold,silver and bronze medal winners' throwing technique.To provide effective technical support for the preparation of the women's hammer event in China for the 2020 Tokyo Olympic Games.Draw the following conclusions:1.The gold medal holds that Wenxiu enters the first circle of rotation after the pre-pendulum is finished,and actively promotes the rotation,completes the double support acceleration of the first circle quickly,shortens the rotation time of the first circle,and obtains a larger increment of the speed of the instrument.Zhang Wenxiu's rotating time from the second to the fourth turns showed a decreasing trend,which accorded with the technical rules of hammer throwing,and the overall rhythm of the rotating stage was better.Silver medalist Rona's sustained acceleration ability declined after four turns of rotation,resulting in a longer final exertion time than Zhang Wenxiu and Liu Tingting,which affected the initial speed of the final shot.From the time allocation of single and double support,Liu Tingting,the bronze medal winner,spends significantly longer time on single support than on double support,which is not in accordance with the time allocation rule of single and double support in hammer,and there is unreasonable phenomenon in rotation technology.2.The gold medal holds that Wenxiu has a strong ability to accelerate instruments anda good grasp of the rhythm of rotational acceleration in the process of rotation.Rona and Liu Tingting were unable to improve their rotation speed effectively and maintain a good hammer speed increment because of their insufficient ability of continuous acceleration during the third and fourth rotation cycles.3.The gold medal holds that Wenxiu's hammer trajectory length value is ideal,reaching a larger radius of rotation,and the ideal trajectory length ensures the working distance of hammer acceleration.The rotation radius of silver medalist Rona and bronze medalist Liu Tingting is smaller than that of Zhang Wenxiu,and the distance of doing work is relatively small,which affects the distance of throwing hammer.4.The gold medal holds that Wenxiu's shoulder chain angle is relatively stable at the moment of the right foot leaving the ground and landing in each circle during the rotation process,which is Zhang Wenxiu's good control of hammer movement,achieves the effect of "human-ball" integration,and creates good conditions for hammer acceleration.Silver medal winner Rona's shoulder rotation is much ahead of the hammer rotation in the fourth and final round of double support,forming the "backball" movement,affecting the overall rotation rhythm and shape.Liu Tingting,the bronze medal winner,fluctuates greatly in the shoulder chain angle at the moment of the right foot leaving the ground and landing during the rotation process.Its stability and coordination need to be further strengthened.