| The purpose of this article: to study the force-testing method of the side-kick in free-fighting, and develop the new field of three dimensional force-testing according to many experiments by means of three-dimensional force plate; to discover the kinematics rules and characteristics of the side-kick in free-fighting through the experimental study on the side-kick's biomechanics and kinematics characteristics of 18 excellent free-fighting athletics coming from Shandong Province, which will provide reliable kinematics indexes and parameters for diagnosing and improving the motion skills of free-fighting side kick,and for free-fighting teaching and training, further systemize and scientize the theory research of free-fighting motion. The research approach: documents and materials, three-dimensional force-testing, planar shooting on spot, film analysis, datum statistics and expert consultation. The results: 1. Research on experiment methods: (1) That the soft sponge fixed on the surface of the force plate with about 15cm thick is suitable as a cushion medium .(2) That the sampling time of the force plate is set to be 5s,which is convenient to datum gathering .(3)That the sampling frequence is 20000Hz can ensure to gather the strength datum to accurately reflect force characteristics. 2. Biomechanics characteristics of the side-kicking motion: (1),Among the selected excellent free-fighting athletics from Shandong Province , for the most force, there is obvious difference between the advantage legs and the disadvantage legs, and the most force of the advantage legs is obviously higher than that of the disadvantage legs; But there is no obvious difference between the advantage legs of the athletics whose advantage leg is the left side, and there is also no obvious difference between the disadvantage legs of the athletics whose advantage leg is the right side. (2) For the average time the athletics need to reach their most force, there is no obvious difference between the of advantage legs and the disadvantage legs; There is also no obvious difference between the advantage legs and the disadvantage legs of the athletics whose advantage leg is the left side, and between the disadvantage legs of the athletics whose advantage leg is the right side. (3) Among the selected excellent free-fighting athletics from Shandong Province ,for the most force, there is obvious difference between the advantage legs and the disadvantage legs of the first-grade athletics, and the most force of the advantage legs is obviously higher than that of the disadvantage legs; But there is no obvious difference between the advantage legs and the disadvantage legs of the Jianjiang athletics, and no obvious difference between the advantage legs of the first-grade athletics and the Jianjiang athletics, and also between the disadvantage legs of the first-grade athletics and the Jianjiang athletics. (4) Among the selected excellent free-fighting athletics from Shandong Province , for the average time the Jianjiang athletics'advantage leg need to reach the most force, there is obvious difference between the advantage legs and the disadvantage legs of the Jianjiang athletics, and the time the Jianjiang athletics is obviously longer than that of the first-grade athletics; But there is no obvious difference between the advantage legs and the disadvantage legs of the first-grade athletics, and no obvious difference between the advantage legs of the Jianjiang athletics and the first-grade athletics, and also between the disadvantage legs of the Jianjiang athletics and the first-grade athletics. 3,Kinematics characteristics of joints in the side-kicking motion: (1).The biggest average resultant velocities of athletics'lower extremity joints respectively are: hip joint (V=2.390±0.345m/s), knee joints(V=5.258±0.585 m/s), toe(V=9.527±0.777 m/s); The biggest average component velocities in the direction of X respectively are: hip joint(Vx=1.889±0.301 m/s), knee joint(Vx=4.807±0.748 m/s), toe(Vx=5.879±0.708 m/s); The biggest average component velocities in the direction of Y respectively are : hip joint(Vy=1.742±0.357 m/s), knee joint (Vy=3.844±0.543 m/s), toe (Vy=7.785±0.860 m/s).All show that velocity gradually becomes increased from big joint to small joint. (2). While athletics'lower extremity is striking, The average resultant velocities respectively are: hip joint (V=1.175±0.437m/s), knee joint(V=3.724±0.995m/s), toe(V=4.264±2.235m/s); The average component velocities in the direction of X respectively are: hip joint(Vx=1.159±0.546m/s), knee joint(Vx=3.035±1.054m/s), toe(Vx=5.879±0.708m/s); The average component velocities in the direction of Y respectively are: hip joint(Vy=-0.388±0.260m/s), knee joint(Vy=0.451±1.228m/s), toe (Vy=2.666±2.032m/s). At the striking time, the velocities are not the biggest, but a little smaller than the biggest. What's more, all component velocities in the direction of X is bigger than that in the direction of Y. 4. Characteristics of the joints'track curve in the side-kicking motion:(1)Comparing with the motion track curve of athletics'supporting-leg, the kicking-leg curve varies greatly with apparent fluctuation ; Its swing scope is obvious in the direction of X and Y; Dot density on the curve is less.(2). Among the motion track curves of athletics'lower extremity joints, fluctuation... |
PDF Full Text Request