Sport Biomechanics Research On The Pitching Movement Of Over-hand Throw Of The Elite Baseball Pitchers In China

In the baseball game, the pitcher technical and tactical level play the role of about 80% to the outcome of the game, which is the soul of the team, as well as a measure of the ability of a baseball team. Each set starts with the pitch in baseball game. Therefore, mastering the changes of pitching speed, way, height, etc is an important way to change from a passive position to an active one. At present, the level of the baseball pitchers in China is not good enough, which needs a sports biomechanics research to meet the need of practice and theory.In this study, Three-dimensional Video Analysis System and Ariel Performance System are used to test the top 16 pitchers from five teams in China. Three-dimensional Video Analysis System and two Kistler force plates (1000Hz) are used to test four pitchers in laboratory. Record the kinematics and dynamics data of the participants. Divide all aspects of the upper and lower limbs of the participants in accordance with Zheng Xiuyuan's manikin. The Sports Biomechanics Principles and Methods are used to test and analyze the pitcher's pitching technique of the outstanding baseball players. Attempt to reveal the kinematics and dynamics characteristics of it, and make a reasonable diagnosis and evaluation to the participants'movement. Objectively analyze the best pitchers'movement in China so as to provide a theoretical and training reference.The conclusions are as following:(1) According to the research on the pitching movement of the best pitchers, the phases of the pitching movement was divided again. Based on the analysis of the characteristics of various stages and the kinematics and dynamics analysis of the key movements, the data of the unreasonable kinetic parameters and kinematics parameters were achieved. This will be meaningful to the sixteen pitchers.(2) The time parameter of the pitching movement is relatively same on each movement phase. But there is a great difference during the knee-axis stage. The average total pitching time is 0.87s. The average stretching time is 0.63s. The average speeding up movement time is 0.05s.(3) Subjects were all the outstanding pitchers. The results show that they have had a relatively high level on pitching movement. There are both many good aspects and deficiencies. Compared with the foreign pitchers, the pitchers in China has a more narrow outreach shoulder joint angle when the leading foot touches the floor. Thus influences the trunk momentum passing to the throwing end because the speed off hand is greatly influenced at this moment. The maximum of Elbow angular velocity is smaller during the accelerating phase than the foreign pitchers; The maximum of shoulder internal rotation angular velocity is much smaller during the accelerating phase than the foreign pitchers; The lifting knee of the leading foot is not abundant enough; knee and hip joint angular velocity is too fast during lifting knee stage which is not conducive to stability.(4)The average of pitcher trunk lean angles and trunk roll angle respectively is 32.97±9.42°and 28.49±17.56°the moment of throwing ball.(5)The appropriate step allows the pitcher in a stable position, and is also beneficial to enable the player to form a greater forward accelerating distance. This will help improve the speed of the ball off the hand. The average landing distance of the pitchers is 1.58±0.10m, sharing 85.65% of the body height.(6)The average ball speed is 32.21±3.43m / s. The speed is much small than the foreign pitchers'.(7)The maximum force and power of throwing upper limb happen at the moment of the ball off the hand in accordance with the pitching movement. But the maximum force of upper limbs of Meng Qingyuan and Wu Haoliang acts behind which can easily make throwing arm lead to injury. (8)In this study, Kistler three-dimensional system was used to study the ground reaction force, impulse and power to the axis foot and the leading foot in different directions. They were studied before and after the pivot foot up and down direction and the direction of the maximum force and power have taken place leading foot in the moment before touchdown 0.1s. Feet before and after leading the direction and vertical direction and the maximum power occurred in the hand at all times about baseball. The lower limb movements in different directions in the ground reaction force, impulse and the force acting in different directions on the pitching power of the impact of the quality and speed for a clearer understanding. In order to improve the pitching techniques from a certain degree of significance and reference value.