The Experimental Research On The Straight Football Collision From The Perspective Of Biomechanics

Research Objective: The thesis intends to study the characteristics of kinematics and mechanics in the football collision from the perspective of biomechanics by using Kistler force-testing plate and JVC video camera of high speed in the hope of discovering the kinematic rules and characters of the football collision and offering a reliable kinematic index and parameter for the football training, match and teaching. It also attempts to provide theoretical support and propel the development of the football sport.Research approach: documentary analysis, Kistler force-testing plate, video camera shooting on spot, the analysis of the camera pictures, the statistics of the data.Conclusion: 1. the research of the experimental method: (1) The sampling time of force plate is set to 5s, which is convenient to do data- testing. (2) The sampling frequence is 200Hz, which can ensure to gather strength data to accurately reflect force characteristics. (3) For the fact that the time of the football collision is so short and that there is much difficulty to control the strength of kicking the ball, the thesis is in great favor of using the video camera of high speed and football shooter.2. the kinematic characters of the football collision. (1) The colliding process with low speed is0.00832s, while the one with high speed is 0.00775s. Obviously, there exists some difference between the two processes. The former is 0.00057s shorter that the later one. (2) The average time when the football reaches the fiercest collision with low speed is 0.00421±0.000639s, and high speed with 0.00317±0.000551s. The time the two processes need is quite different. (3) The reinstatement coefficient of the football is determined by its elasticity. In the collision with low speed, the reinstatement coefficient of the football is 0.838, and 0.736 with high speed. The former one is 0.102 more than the later. (4) There is little difference between rebounding speed and launching speed when it is in low process, but in high speed, it is quite different, which indicates that there is much relevance between the rebounding speed and launching speed in low speed, but little relevance between the two in high speed. (5) The loss of kinetic energy is different. The average loss rate in low speed is 29.8%, and 45.8% with the high speed. The loss of the kinetic energy rises with the increasing speed.3. The mechanical characteristics of the football collision: (1) the collision in low speed or in high speed. The power curve of the two cases both belongs to the mono-climax and concussion power. They both reach the maximum of the power in extremely short time, then falling into minimum dramatically; (2) the relevance between the impulse and launching speed is 0.9372, while the relevance between the average power and launching speed is 0.8515. The two factors with the launching speed are in direct ratio, and the impulse has the closest relations with the launching speed.