A Modified Lift Mechanics Theory for Downhill Skiing and Snowboarding (P239)

Abstract

In a recent study, Wu, et al. (Med. Sci. Sports Exerc., Vol. 38, No. 6, pp. 1132–1146, 2006) have developed a new mathematical model to describe the lift mechanics of downhill skiing and snowboarding, where the lift contributions due to both the transiently trapped air inside a snow layer and the solid phase (snow crystals) were determined for the first time, and a model for the stability and control of skiing/snowboarding was developed. The lift generation highly depends on the permeability of snow, speed, friction, as well as the geometry of the ski/snowboard. In the current study, we shall extend Wu et al.’s theory to more complex planar shapes. A modified mathematical model is developed where a width factor, f(x), which characterizes the variation of width from the leading to the trailing edge of a snowboard, is introduced. We shall thoroughly investigate the force and moment balance on the planing surface due to the trapped air and the snow crystals, and examine their effects on the stability and control of a ski and snowboard. The performance of different commercial snowboards will be examined based on our revised model. This study and the previous lift mechanics theory for downhill skiing and snowboarding developed by Wu et al. have laid the foundation for the optimization of a ski/snowboard from a lift generation point of view.