| Through related literature research, uneven bars champions in the world gymnastics competitions are found to get high scores because of the perfect connection actions. Currently, most researches among the uneven bars both at home and abroad are only focused on the theoretical summary, such as research of uneven bars' technological development, uneven bars study on the choreography of whole-set movement, etc., however, studies of the whole-operation kinematic analysis are seldom found. In addition, research of analyzing on the uneven bars connection action by using both the three-dimensional video analysis method and 3D virtual reproduction technique has not been reported yet. While the technical moves of the world's best athletes can be considered to be a reasonable technology and a very valuable model,which are consistent with the bio-mechanical rules and principles. Therefore, making further research on the technical structure of the connection actions by the national champion Shang Chunsong, and looking for the actions' characteristics and patterns will have important reference values in training athletes.In this paper, three-dimensional video analysis method was been taken to focused on Shang Chunsong's uneven bars actions of the final competition in 2013 National Games and the immersive virtual reality technique was used to reappear Shang Chunsong's final moves, then analyze Shang Chunsong's actions of Tkatchov split and Gienger Salto on the perspective of sports bio-mechanics, thus revealing these moves' bio-mechanical principles and rules and providing references for the athletes' technical training, and will also enrich the theory of uneven bars connection technology.By analyzing Shang Chunsong's moves, relevant kinematic parameters were acquired. Following conclusions were drawn after deep-going analysis:Tkatchov split action: while at the moment when Shang Chunsong was at the lowest position under the bars, her left and right shoulder angle were 175.6° and175.2°, the left and right hip angles of 196.6° and 195.4°, the left and right knee angle of 170.5° and 171.5°, with the body in arched position. At the end of pocket leg process, the center gravity of her body was under the bar horizontal, and it was ended relatively early, so it was completed not good enough. When the center gravity of her body swung to the back of the bar horizontal, the left and right rankle resultant velocity reduced to 5.44m/s and 5.49m/s, while the left and right shoulder resultant velocity increased to 2.30m/s and 2.29m/s. And at this moment, her body center of gravity resultant velocity was 3.47m/s, with left and right shoulder angle increased to 137.4°and 140.3° and left and right hip angle increased to 113.0° and 113.5°, which showedthat her action of traveling lunge was not stretched enough and that her lifting shoulder action was not obvious enough. At the moment Shang Chunsong releasing the bar, her vacated height was 0.70 m, with her body center of gravity much higher than the bar horizontal. From the moment under the bars to the moment releasing, it was 0.58 s. She chose a very good releasing moment that she could get a sufficient vacated height.When the moment she holding the bar again, the vertical distance between her body center of gravity to the bar horizontal was 0.23 m, with the center of gravity higher than the bar horizontal. At this moment, the center of gravity's radius was 0.67 m, and the grip angle of 30.1°, the left and right shoulder angles of 140.0° and 141.5°, showing that at this moment the grip angle, height of the center of gravity and the center of gravity's radius were relatively big, which played an important role in increasing the gravitational torque in the downswing stage.Gienger Salto action: when the moment Shang Chunsong's hip angle reached to the maximum while downswing, her body was in a back bending position, with her left and right shoulder angle of 172.9° and 176.8°, the left and right hip angle of 218.0°and 219.2°, and the center of gravity resultant velocity of 4.45m/s. When she was at the lowest position under the bars after griping the bar, the left and right shoulder angles were 164.3° and 166.1°, and the left and right hip angles were 206.5° and204.0°. When the moment Shang Chunsong releasing from the bar, she first spread her left hand with a little twist towards left and then let her right hand free, which helped to complete the Gienger Salto action. When she free her right hand, her body center of gravity was lower than the bar horizontal, with height of the center of gravity of-0.01 m, the center of gravity' radius of 0.67 m, the left and right ankle velocity of4.34m/s and 4.36m/s, the left and right shoulder velocity of 3.61m/s and 3.62m/s.When the moment her gravity reached the highest point while somersault, the vertical distance between the body center of gravity to the bar horizontal was 0.48 m, with her left and right shoulder angle of 21.6° and 26.6°, the left and right hip angles of 100.6°and 100.9°, the left and right knee angle of 179.0° and 172.3°, and her body gravity's vertical velocity of zero and the resultant velocity of 0.35m/s. When her right hand griping the bar, her left and right shoulder angles were 93.7° and 106.3°, with the left and right hip angles of 142.0° and 134.3°, the left and right knee angle of 176.7° and173.9°, and the body center of gravity resultant velocity of 2.69m/s. For this moment,her two-hands hold the bar, and the holding bar angle was 15.7°, while her center of gravity was slightly higher than the bar horizontal, with the height of the center of gravity of 0.02 m and the center of gravity's radius of 0.55 m.Shang Chunsong had completed the Tkatchov split and Gienger Salto movements well. |
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