Kinemics Research On The Last Step Of Run-up And The Skills Of Swinging Leg In The Take-off On Elite Women Long Jumpers In China

With the development of sports science, people realized that any improper movement during run-up and take-off had negative effects on the results of the long-jump. Therefore, it is necessary to analyze every movement in the stage of the take-off to obtain the high scores. People also observed that the support and the skills of the swinging leg were the most important components in the take-off. Therefore, this paper defined the starting movement of the take-off as the instantaneousness of the pedal and stretch following the swing leg, the support and the cushion. This paper analyzed the characters of the movements of the take-off as well as the movements of the swing leg to obtain the main points of the long-jump for the teaching and training class, with the expectation that this research will lead to the technology optimization of the take-off of the woman long-jump athletes in our country.The first six women candidates for the final long-jump game in the 10th National Games held on October 23, 2005 were chosen for study in this research. The methods included the literature search, the visit survey, the film shooting, the image analysis and the statistics analysis used for analyzing the characters of the take-off. The results showed that:(1) The average height of the long-jump female athletes from the our nation is oustanging women is long jump was significantly shorter than that of the international, elite ones, but the average height of our elite athletes was much better. The absolute weight and the relative weight of our athletes were significantly smaller than those of the international elite athletes, indicating that the quality and the density of muscle of the participating athletes in this game were significantly worse than those of the international athletes. The age of our long-jump athletes was relatively small (22-23) when they achieved their best scores, the time they spending on training was relatively short (more than seven years), and the period that they maintain a highest score was too short (three years). (2) The low velocity of the swing leg and the improper movement of the coax forwarding in the last run-up resulted in the big support angle of the swing leg. This would be the main reason that caused the low level of our athletes. During the last pedal and stretch, the big knee angle of the swing leg, the imperfect performance of 'the bend-stretch' lagged the start of the swing leg.(3) The swing angle during the jump of our elite female athletes was 704.378.±78.563°/s. This was the main factor affecting the vertical take-off velocity, the flight velocity, and the last scores of the long-jump.(4) The swing velocity and the angle changing between two legs had direct effects on the gravity velocity and the vertical movements of the body in the buffer stage of the landing.(5) The 'sudden-stop' skill of the swing leg before the jump had effects on the pedal and stretch of the take-off. This also had significantly effects on the body hoist during the jumping, the velocity and the scope of the coax extending, and the scores of the long-jump.(6) The swing velocity and the swing skills (the swing performance, the swing time and the swing extent) had highly effects on the score of the long-jump.(7) The kinematics characters of the swing-leg during the jumping of our women's long-jump athletes were: swing acceleration after the jumping, the swing angle increasing to the maximum at the buffer stage, the angle decreasing at the stage of the pedal and stretch to the stop at last. Its characters were consistent with the biomechanics principle of the sports.