Biomechanic Research For Four Kinds Of Tennis Serve In Our High Level Tennis Players

Purpose:We use VICON motion capture system to know the relation between different serve type through analyzing the kinematic and kinetic data of different serve together with EMG information, it will contribute to the theory and reality for the injury prevention and rehabilitation.Method:We choose ten tennis professional players from Beijing Sports University to test first serve with FB, second serve with FB, first serve with FU and second serve with FU using VICON motion capture system and EMG device, in order to calculate the kinematic, kinetic data and EMG information.Result:From the kinematic data, we can see that the lateral flexion separation angle (LFA), lateral alignment rotation (LAR) of first serve is higher than that of second serve, however left and right knee joint flexion-extension (KJFE) and shoulder alignment lateral flexion angle (SALFA) is lower than that of second serve, Separation angle (SA) is not different.Compared with FB and FU, lateral flexion separation angle of FB is higher than that of FU, left and right knee joint flexion-extension, lateral alignment rotation and shoulder alignment lateral flexion angle is lower than that of FU. From the kinetic data, we find that maximum shoulder torque(ST) of first serve is higher than that of second serve, maximum shoulder torque of FB is higher than that of FU no matter if first or second serve. Regarding the EMG information, the EMG volume of deltoid about first serve with FU and second serve with FB is highest.But the EMG Volume of pectoralis about the first serve with FB and second serve with FU is highest. Their order is same. The EMG volume of low limb is same too.Conclusion:1. we can see that the lateral flexion separation angle, lateral alignment rotation of first serve is higher than that of second serve, however left and right knee joint flexion-extension and shoulder alignment lateral flexion angle is lower than that of second serve, we think that first serve can produce more loading, maximum shoulder torque of second serve is higher that of first serve, second serve with FU is considered as a economic serve type because its joint loading is most lower and its torque is highest.2. Maximum lateral flexion separation angle of FB and FU is different with their occurrence time. Compared with FB and FU, left and right knee joint flexion-extension, lateral alignment rotation and shoulder alignment lateral flexion angle of FB is higher than that of FU. The shoulder torque of FU is higher than that of FB.3. Regarding EMG information, EMG volume of deltoid about first serve with FU and second serve with FB is highest. But EMG volume of pectoralis about first serve with FB and second serve with FU is highest, their order is same. EMG volume of low limb is same too.4. The activation time of shoulder muscle in four types of serve is same as:deltoid, brachilis, trapizius, brachioradialis, obliquus externus abdominis, ectopectoralis, rectus abdominis, latissimus dorsi.