The Technical Analysis Of Smash In Chinese High Level Women Sitting Volleyball

Smash is one of the most important skills in sitting volleyball. Owing to the particularity of the Paraplegics' sports, the smash skill in sitting volleyball is different from the Able-bodied volleyball, so it should be analyzed independently. The researches on sitting volleyball drop shot skill will be consolidate the aggressivity of the Sitting volleyball and provide the theory support in the practical training.This research camera the research objects in three different positions, process and analyze the collected data after import it into the vicon system. The article unifies the related theory, summarize the kinematical data of the sitting volleyball, enrich and consummate the theory of smash skill in the sitting volleyball.Firstly, in the initial stage of sitting volleyball smash which is also when the arm swing in its maximum, there is a significant correlation between the trunk angle when it's in the arm swing's maximum stage and the speed of the smash. When the arm swing reach to its maximum, the appropriate angle of the shoulder abduction can be good for the twist of the body and provide more strength and more speed for the upper arm. The initial angle of the shoulder abduction of research object is about 136 degree, and this paper thinks this is the most appropriate angle for the shoulder abduction to some extend. All the research objects' elbow were bended and the body were draw back, and this kind of arm swing can increase the radius of arm swing and thereby increase the linear speed of the arm. Compare with the 63.8 degree which is the angle of the able-bodied men's elbow bending, the sitting volleyball players'angle is larger. It is correlate with the particularity of smash in the sitting volleyball. The angle of the wrist joints has little effect to the smash, but proper wrist relaxation can have positive effect to the momentum transmission.Secondly, from the maximum stage of arm swing to the moment of hitting, the angular rotation of the elbow joint reflect radius of gyration of the upper arm, and it also concerns the promotion of upper arm's linear speed. The proper angular rotation of the elbow joint can increase speed of the hitting arm. In the stage of arm beat action, the angular displacement of wrist joints is less than the angular displacement of elbow joints, but when the angular displacement of wrist joints is small or negative; it can affect the angle of hitting and decrease the effects of smash.During the arm beat action, the accelerated speed of elbow joints and wrist joints can reflect the influenced process of speed and the variation of strength indirectly and it has proved the transitivity and increment of the players' hitting strength.Thirdly, in the hitting moment of the sitting volleyball, the variation of angle and speed in each link would have a great impact on the smash effect. In the hitting moment, the angle of shoulder joint can determine the height of hitting point and the speed of ball. In this paper, the hitting angle of elbow joint is 120 degree, this angle can exert the acceleration effect of upper arm and forearm. It corresponds with the anatomy and kinematical theory. Simultaneously, owing to the particularity of sitting volleyball, the angle of elbow joint in the hitting moment is less than the value of able-bodied men's angle. The angular speed of each link in the hitting moment represents a status of increment and it demonstrates the process which momentum transferred from the head of chains to the end. There is also a significant correlation between the ball speed and the speed of wrist joint in the smash. Most of the players flex the wrist for the hard shot to increase the speed, but theoretically, increase the linear speed of hands can have positive effect to the smash.The height of hitting in the hitting moment would not affect the speed and strength of the smash but it have certain relationship with the over-net rate, with the addition of trucal stationarity in sitting volleyball smash, players can master the proper hitting point and height easier.