Spörri Jörg, Kröll Josef, Gilgien Matthias, Müller Erich
Department of Sport Science and Kinesiology, University of Salzburg, Hallein-Rif, Austria.
Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway.
Br J Sports Med. 2016 Jan;50(1):14-9. doi: 10.1136/bjsports-2015-095737.
There is limited empirical knowledge about the effect of ski geometry, particularly in the context of injury prevention in alpine ski racing. We investigated the effect of sidecut radius on biomechanical variables related to the mechanics of turning.
During a field experiment, six European Cup level athletes skied on three different pairs of giant slalom (GS) skis varying in sidecut radii (30 m, 35 m and 40 m). Using a video-based three-dimensional (3D) kinematic system, a 22-point body segment model of the athletes was reconstructed in 3D, and the variables ground reaction force, centre of mass (COM) speed, COM turn radius, ski turn radius, edge angle, fore/aft position and skid angle were calculated.
While steering out of the fall line after gate passage, ground reaction force significantly differed between the 30 m and 40 m skis and between the 35 m and 40 m skis. These differences were mainly explainable by larger COM turn radii when skiing on the 40 m ski. During the same turn phase, significant differences in ski turn radius also were found, but there were no differences in edge angle, fore/aft position and skid angle.
The sidecut-induced reduction in ground reaction force and the sidecut-induced increase in centre of mass and ski turn radius observed in this study provides indirect evidence of reduced self-steering of the ski. Self-steering plays a central role in the mechanism of anterior cruciate ligament rupture in alpine ski racing.
关于滑雪板几何形状的影响，尤其是在高山滑雪比赛的 injury prevention 背景下，实证知识有限。我们研究了侧切半径对与转弯力学相关的生物力学变量的影响。
在一项现场实验中，六名欧洲杯水平的运动员在侧切半径不同（30米、35米和40米）的三双不同的大回转（GS）滑雪板上滑行。使用基于视频的三维（3D）运动学系统，对运动员的22点身体节段模型进行3D重建，并计算地面反作用力、质心（COM）速度、COM转弯半径、滑雪板转弯半径、边缘角度、前后位置和滑行角度等变量。
在通过旗门后驶出滚落线时，30米和40米滑雪板之间以及35米和40米滑雪板之间的地面反作用力存在显著差异。这些差异主要可以通过在40米滑雪板上滑行时更大的COM转弯半径来解释。在同一转弯阶段，滑雪板转弯半径也存在显著差异，但边缘角度、前后位置和滑行角度没有差异。
本研究中观察到的侧切引起的地面反作用力降低以及侧切引起的质心和滑雪板转弯半径增加，为滑雪板自转向降低提供了间接证据。自转向在高山滑雪比赛中前交叉韧带断裂的机制中起着核心作用。
