Bai Yan Chen Thirty Tennis Serve Biomechanics Analysis

The serve is one of the most important strokes in the game of tennis,and also the only way of hitting the ball without the influence of the rival.It is the start of the rivalry and the attack.Well-prepared tennis players can get winners directly or make good conditions for the following attack.The competition skills of tennis are still not so good in China and coaches'diagnosis to the high-level players'movement bases on the observation with the naked eye and subjective estimation.In this study the serves of the two excellent yang tennis players Bai Yan and Chen Sa were kinescoped in matches and a series of data and parameters related to physical kinematics was achieved through document method,three dimensions kinescope and consulting with experts.Meanwhile the article makes an overall and systematic qualitative and quantitative analysis to the obtained data and parameters from the perspective of each segments locus features.The purpose of the study was to obtain and analyze the kinematics features of power serve and to help the coaches to judge if the subjects' skill was reasonable.We want to provide a theoretical reference of the theory and training of tennis serve.The analysis suggests that the good direction,the adequate height of toss, knee flexion and scope of lower limb extension are the great influence to the whole movement of one of the players Bai Yan.His backscratch action was not adequate in the first serve,which results in the inadequate extension of the abdomen and higher limb muscles,and the hitting speed was influenced by the low acceleration of the middle-body and lower limbs because of his injuries in waist but the whole movement was an excellent whip action with a proper height of impact.The other player Chen Sa takes the FU stance,sideswing upward but he did not have adequate knee flexion in the first serve,which leads to the low center of his gravity when he hit the ball.His two serves are adequate backscratch action with high and proper direction of toss which makes up the inadequate knee flexion,so his racket head was swung fast in a comparatively long time in the air.His overdependence on the power of his body and joints of the lower limbs to accelerate his speed of hitting decreased the accuracy of serving,and his lower height of impact results from the inadequate flexion of his lower limbs,but his whole movement accords with the whip action basically.So he should emphasize on the power training of his lower limbs.