Abstract
The purpose of this study is to closely examine kinematic features by jump stage of Ropez motion in horse vaulting and clarify effective rotation and twist movement of the body. For this, as a result of analyzing kinematic variables through three-dimensional images using high speed video camera to Ropez motions performed at horse competition, for men events, gymnastics, the 14th Busan Asian Games, and comparing them with the precedented research into Kasamas line skills(Park, Jong-hoon, 2001, 2002; Lee, Soon-ho, 2001), the following conclusion was obtained. 1. It was indicated that at the post-flight, the increase of flight time and height has an critical effect on that of twist extent, and when the COG reached the peak, the rotation angle of the trunk does not secure the complete bwd, salto, but the twist angle of the trunk already forms 270˚. This means that the efficacy of twist motions is enhance since rotation motion is restrained, and mass is closely distributed to the rotation axis of twist. 2. It was indicated that at the contact of the board, the angle of hip and knee joints is large, and rotational velocity of trunk is slow, so the horizontal distance of COG gets small and time of contract become longer at the treading time. This is derived from the fact that the touch-down of horse becomes easy according to the horse standard`s change, so the body stands up in advance and approaches the board. 3. It was indicated that at the pre-flight, horizontal moving distance and flight duration are very short, and the moving velocity of COG and the angular velocity of the body`s rotation and twist are very slow, so the flight is made to a very small extent. This is because of the intention to quickly lean on the horse, and lower blocking angle. 4. It was indicated that at the contact of the horse, Ropez movement shortens contact time and horizontal displacement, and enlarges shoulder angle. This means that it provides increased vertical rise by restraining the push of the body forward, and making the body take-off before it reaches the vertical state. Also at the phase of contacting the horse, the horse touch-down is formed aside, but the trunk is formed in the same way of handspring skills, and this indicates that the body has already made a nearly half twist after horse take-off, contributing to enhancing the effectiveness of twist according to special sense.