A Comparative Analysis Of The Kinematics Of The Male Tennis Player's Slamming Technique

That tennis technology is very difficult to acquire has not only plagued tennis enthusiasts and amateur tennis players,but also plagued the Chinese excellent male tennis athletes.The technical problems make the Chinese male athletes very difficult to get good ranking in various international tennis tournament.Now,the development trend of men’s tennis focus on speed,comprehensiveness,stabilization,offensive and change,and women’s tennis is trend to become masculine,which can clearly see that tennis technology must be comprehensive and also with the good strength and high speed.So tennis serve technology is the one that have to mention.The start of the tennis game is both the serve and the start of the active attack by the serve player.Once the serve can not make trouble for the receiver to catch and reserve the ball,the service game will be in a dilemma,which can be said that the tennis serve with fast speed and very bad angle for receiver is the magic weapon to win.While domestic outstanding athletes still can not be sure to guarantee the serve advantage,which showed in that the speed and serve angle are inferior to the international elite athletes.In this paper,through the literature research and three-dimensional video analysis of the international outstanding athletes Novak Djokovic and Marin Cilic’s inside pitch video,technical characteristics data was obtained,which can not only help the tennis athletes of national standard of level two to improve the serve technical,but also can provide some technical reference for excellent athletes to improve the serve technical.Through the analysis,Djokovic and Cilic’s technical action are in line with the researchresults of domestic and foreign experts and scholars: both of them use foot-back serve technology;their technical action are whipped category,which showed in the smooth swing and force,with full pedal of lower limbs,which bellows to the large joint drive the small joints sport,also a kind of the proximal joint to the distal joint transmission,which made a good serve demonstration for tennis athletes of national standard of level two in Chengdu Sport Institute.Compared with the international outstanding tennis athletes,during throwing the ball and holding the racquet stage: at the moment that the ball leaving the hands,these four athletes’ left elbow are not straight,only Xu ** more close to the standard.As for shot speed,Zheng **’s performance is more stable,while Wang **’s shot speed is too fast.In terms of height of the shot,Zhao ** and Xu **’s shot point are slightly higher than their height,while Zheng ** and Wang **’s are slightly lower than their height.At the moment when bending their knee to the maximum,among the four students,in terms of the right shoulder and right elbow angle,only Wang **’s is more reasonable;while Zhao **’s shoulder is outside the spin,with the outreach too large;and Xu **’s right elbow flexion is not enough;while Zheng **’s right shoulder outreach is not enough,with his right elbow slightly clamping.The performance of the lower extremity joint: all these four’s left knee angle are smaller than the right knee angle,which shows that at end of holding the racquet,the center of gravity of the athletes are in their left leg;while during the entire stage,their wrist are in a relaxed state,and Zheng ** and Wang **’s shoulder and hip projection angle are bigger than the international outstanding athletes.Back shot stage: compared the height of the body center of gravity with the height of the lowest point of the back of the shot,no one of these four’s center of gravity higher is higher than the height of the lowest point of the back of the shot,and all these four’s back full bow position are not enough or their shoulder angle,Elbow angle and the wrist angle’s flexion and extension are not enough,thus caused insufficient back shot.Swing and hitting the ball stage: four athletes take the same serve posture of the international excellent tennis athletes,foot-back posture;in terms of drop height,Zheng **and Xu **’s are respectively 0.353 m and 0.512 m,while Zhao ** and Wang **’s arerespectively 0.847 m and 0.753 m.This study suggests that the higher of the hitting point height the better,thus can increase the scope of the attack range.Zhao ** and Wang **should reduce the drop of the throwing point so as to help to improve stability of the hitting.The maximum speed of the he the shoulder,the elbow,the wrist on the side of holding the racquet and the ball of Marin Cilic during the swing and hitting the ball stage are: 5.10m/s,8.53m/s,13.87m/s,26.83m/s.the maximum speed of the shoulder,the elbow,the wrist on the side of holding the racquet and the ball of Novak Djokovic during the swing and hitting the ball stage are: 4.98m/s,8.36m/s,13.73m/s,25.92 m/s.Compared with the international excellent tennis athletes,In view of the data of the upper limb joints,four athletes’ s action are also belong to whipping action category.Their head speed: Zhao *(22.67 m / s),Zheng *(23.89 m / s),Xu *(24.48 /m s),Wang *(23.31 m / s)four national tennis players are inferior to international outstanding tennis players.Follow through stage: In the respect of the time of the entire serve,four athletes’ buffer time are too long at this stage,which is not conducive to return the next ball back.