A Method of Representing Carving Turn Posture

• Published in: Journal of Ski Science Vol. 1; no. 1; pp. 1 - 8
• Main Authors: HASEGAWA, Kenji, SHIMIZU, Shiro
• Format: Journal Article
• Language: English; Japanese
• Published: Japan Society of Ski Sciences 2003; 日本スキー学会
• Subjects: animation; carving turn; center of gravity; computer; wire frame
• ISSN: 1349-449X; 1884-1422
• DOI: 10.14845/jskisciences2003.1.1

We developed a method of representing carving turn postures of skiers by computer simulation. We assume the following conditions for repeated carving turns. (a) A skier is represented by a wire-frame figure and its posture is fixed by the values of the joint angles. (b) Both skis are always parallel and in contact with the snow surface. (c) The slope of the snow surface is constant everywhere. (d) At the instant of switching the direction of a turn, the skier takes a symmetric posture like straight downhill on a flat plane. The values of the edging angle of both skis are always the same. Given the values of the edging angle and the distance between the tops of both skis, the form of the lower body of the skier is determined. Subsequently, the form of the whole body of the skier is determined by the angle between the upper body and the left/right femur. Assuming the range of variation of each joint angle and changing the edging angle synchronously with the movement of the left/right ski along a circular rack on the slope, we can show the animation of a turning skier with skis by computer simulation. The position of the center of gravity of the skier is also shown at each instant.It turns out that a video record of a carving turn played by a skier, chosen arbitrarily, is well reproduced by our computer simulation. The method proposed here is expected to serve as a tool of technical analysis and instruction in skiing technique.