| In recent years,with the rise of a number of outstanding tennis women players such as Li Na and Zheng Jie,not only has it attracted the attention of the world professional tennis,but it has also set off a wave of tennis in China.However,it is undeniable that on the whole,the development level of tennis in China still has a certain gap compared with that in Europe and the United States.Especially after a number of excellent tennis players such as Li Na and Zheng Jie retired,Chinese women's players are also difficult to complete.It has shown strong competitiveness in the competition.The reason is that there is a problem in the new and old alternate links.The practice of the world's competitive sports power shows that the youth training system is an important cornerstone of the development of competitive sports.With the advancement of racket technology and the overall improvement of athletes' physical fitness,the bottom line style has become the mainstream of today's tennis.Therefore,the strong bottom line forehand hitting technique is the important weapon for most tennis players to restrict opponents and attack the city..In general,the best young tennis players at home and abroad represent the highest level of youth tennis in the world today,and its action technology is highly valuable.This article uses three-dimensional video recording of the two women's singles semi-finals of the 2017 International Network Youth Masters(also known as the ITF Youth Masters)held in Chengdu in October 2017.From the perspective of biomechanics through analysis software.Kinematic analysis of the bottom line forehand shot technique of four players was carried out,and the following conclusions were obtained:1 At the end of the Swivel Lead,the right knee angle(141.92 degrees)of Osuigwe is small,which affects the right leg kicking and stretching effect in the next swing stage;Carle's body center of gravity is between his legs at this time,which is not conducive to maintaining body balance in the batting process;Osuigwe and Kostyuk's swing range is not enough,which is not conducive to increasing the swing distance in the front swing stage.2 The arc racket technique is used by Osuigwe and Carle,while the straight racket technique with traditional traces is used by Kostyuk and Juvan,which is not conducive to the establishment of smooth batting rhythm.3 At the moment of hitting the ball,Carle's shoulder hip angle is 11.45 degrees,and hitting point is backward,which is not conducive to the shift of body gravity center and forward pressure during hitting,and affects the quality of hitting.At this stage,the torsion amplitude of body trunk(38.32 degrees)is small,and the release of elastic potential energy is poor.4 In the front swing stage,players can effectively improve the control ability of the bodyand hitting structure by reducing the right shoulder angle;in this stage,Carle's right elbow angle is reduced by 14.45 degrees,and there is elbow bending action in the hitting process,which destroys the stability of the hitting structure and easily increases the load on the elbow,leading to the generation of tennis elbow.5 In the batting process,the right wrist of the four players is not fixed,and they take part in the active batting after the racket touches the ball.6 The forward swing action of two players,Osuigwe and Kostyuk,conforms to the coordination law of multi-link movement.The timing of deceleration and braking(along the coordination chain)is transferred from the proximal end to the far side in turn.The forward swing action of Juvan satisfies the coordination law of multi-link movement,while the forward swing action of Carle does not conform to the principle of multi-link movement.7 At the moment of hitting the ball,the speed of the head will drop slightly due to the impact of the ball.8 Carle follow-up stage takes less time(0.14s),and the hitting structure quickly bypasses the body,which is not conducive to improving the speed of the ball. |
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