신장대비 하지길이 비율에 따른 유도 허벅다리걸기 기술의 운동학적 분석

Abstract

In this study, the subjects were divided into two groups according to the ratio of leg length against height, which is one of the anthropometric factors, and kinematic analysis of Koshi-uchi-mata, a leg technique frequently used in various weight classes of judo, was performed to investigate the effect of the length of the leg on the performance of Koshi-uchi-mata. 3D movement analysis was carried out using 10 subjects, who have had at least one experience of winning in national competitions, and dividing then into a group of 5 subjects with long legs and another of 5 subjects with short legs. The analysis was based on three specific factors, time factor, posture factor and kinematic factor, that have to be considered when Koshi-uchi-mata technoque is to be performed effectively. Results are as follows： First, Time Factor：The group with longer legs took shorter time than the group with shorter legs in throwing the opponent over. Both group took longest time for tipping segment of the technique. It was found that, in order to shorten the overall time to perform the Koshi-uchi-mata technique, shortening the time taken for tipping would be the most effective way of shortening the performance of the whole technique in which the group with longer leg compared with height is advantageous.Second, Posture Factor：The horizontal shifting of weight center during Koshi-uchi-mata was greater in the long legged group during tipping but was similar during actuating. It was greater in short legged group during throwing. The forward-backward shifting of weight center increased from tipping until posturing but was constant from actuating. The body center was lower in the long legged group indicating that long leg is more effective to maintain low posture and to throw the opponent over. The results of the analysis of the performance of Koshi-uchi-mata technique of judo investigated on the groups with different height-leg ratio indicated that the group with longer legs is advantageous in that they and can throw the opponent over within the shorter period of time and can hold their body center lower maintaining more stable posture. This group also showed faster in angle speed and angle acceleration of major joints of the body and performed better in the turing of the body. These results suggest that the ratio of the length of the leg against body has great influence on the performance of Koshi-uchi-mata and those with higher ratio of leg length are more effective.