Research On Kinematics Throwing Technique Of Two Chinese Elite Female Hammer Throwers

Objective: Women's hammer is an advantageous project in China's track,and a number of outstanding athletes emerged,such as the 2016 Rio Olympics runner up ——Zhang Wenxiu,and now the Asian record holder ——Wang Zheng.Based on the similar competition results of Zhang Wenxiu,Wang Zheng,the two athletes throwing technique kinematic analysis,it will find out their technical movements the advantages and disadvantages,so that they could learn from each other,for further improving and perfecting the throwing technique for reference.Methods: using two CASIO EX-FH25 high speed camera,one places directly behind the throwing direction,another is placed perpendicular to the throwing direction,shooting frequency of 120 frames /S,axis angle of about 90 degrees,the shooting distance throwing circle center about 10 meters,the camera from the ground about 1.2 meters high,on 2014 Chengdu Zhang Wenxiu cast a long game and Wang Zheng 2014 Beijing international challenge scene 3D shooting,Zhang Wenxiu selected the 74.77 metre race material and Wang Zheng 74.71 meters from the use of APAS material,the motion analysis software on the two member of the cast movement The kinematics analysis is carried out by throwing techniqueResults:(1)Complete the throwing action Wang Zheng used 2.233 seconds,Zhang Wenxiu used 2.367 seconds.Zhang Wenxiu in the third circle single and double support respectively for 0.242 seconds,0.225 seconds,fourth single and double ring support respectively for 0.242 seconds,0.216 seconds.(2)According to Wang Zheng hammer's velocity curve,in second,third,fourth in the maximum rotation speed of the ring in the ring of the single support phase.Zhang Wenxiu,Wang Zheng Fourth Ring velocity increment were 1.67m/s,1.7m/s,two in the first ring velocity increment is respectively 2.95m/s,2.27 M/s.(3)The first ring to fourth ring bevel hammer trajectory of the angle of Wang Zheng was 29 degrees,33 degrees,39 degrees,44 degrees angle is 43 degrees.Zhang Wenxiu in second,third,fourth ring support rotating stage,right foot landing moment,hammer the azimuth angle was 269 degrees,257 DEG,267 DEG.(4)According to Wang Zheng's left knee joint angle change curve,it was found that her left knee during the rotation angle of joint maximum value appeared before the right foot off the ground.Zhang Wenxiu instantly shot around the knee angle was 158 degrees,148 degrees,and Wang Zheng left knee angle is 145 degrees,124 degrees.Conclusion:(1)Wang Zheng on completion of the throwing action for shorter time compared with Zhang Wenxiu,reflects the characteristics of Wang Zheng movement speed.Zhang Wenxiu in the rotation of the third and fourth ring single double support time structure is not reasonable,affect the acceleration effect of the rotating rhythm and the hammer.(2)Wang Zheng in second,third.Single support phase fourth laps,when the position of the hammer movement to the highest point,appear to have pulled the ball force.Zhang Wenxiu,Wang Zheng's Fourth Ring velocity increment is less than the first circle increment,showing the characteristic of weak instruments continues to accelerate.(3)Wang Zheng in the third and fourth ring track inclined hammer movement angle the change is not reasonable,Directly affect her angle.Zhang Wenxiu in the rotation in the single support phase right there fell to the ground slowly phenomenon.(4)Wang Zheng's right foot landing position side,causing the double support phase leg stretching is not reasonable.Wang Zheng instantly shot around the knee angle,the angle is too small,that the final stage of leg extension is not sufficient.