Kinematic Analysis On The Lower Limbs Technique Of Excellent Man Tennis Back-ups In Jiangsu Province

In this paper, four elite junior tennis players of the junior sports school in Jiangsu Province as the research object. By using the two Mega high-speed cameras with shooting frequency of 300 frames / second, exposure time of 1 / 2000 second synchronization , using the framework of"peak"in the standard tennis court to collect three-dimensional motion image data, and adopt the German SIMI-Motion analysis software to analysis the images, and using the methods of research such as literature, image analysis, logic analysis, statistics and other research methods, selecting center of gravity, link centroid and other inertia parameters, and link speed, angular velocity, displacement and other movement parameter index,to analysis the lower limbs movement in the process of forehand and backhand of the four junior tennis players. Reflecting the problems according to feedback time and space parameters about lower limbs and lower limb coordination, as the attention in train in order to improve the ankle, knee, hip and lower limbs coordination in the different stages and lower limbs transmission, while providing data on lower limb kinematics chain parameters, also for junior tennis players in Jiangsu Province to improve the tennis ball technique to provide data. Study results showed that the main results: (1) The player of Ma XX is in course of forehand hitting, speed of ankle produce later , the timing of pedal is incorrect. Wu XX's variation amplitude of ankle is not obvious, can not produce a good effect of pedaling. (2) The action of forehand hitting topspin, all players completed the process of pedaling and stretching, knee angle of minimum legs less than the reasonable point of view in general, and the knee angle of the minimum leg below the knee angle of supporting the leg. Topspin of the backhand hitting, during the test time the players are about knee angle before the ball during the preparation of the extent of the left knee angle is greater than the right knee angle, and left knee angle is too small of ZengXX. (3) The players are hitting topspin ball in forehand, the hip angle increase from ready to hit, limited hip angle backhand with both hands, in addition to Liu XX, the remaining members change little. (4) All players used to adjust the legs to the body center of gravity will produce relatively unstable.