Aachen University of Applied Sciences, Institute of Bioengineering, Heinrich-Mußmann-Str. 1, 52428 Jülich, Germany.
Medical University of Graz, Institute of Biophysics, Neue Stiftingtalstr. 6 (MC1.D.)/IV A, 8010 Graz, Austria.
J Biomech. 2019 May 9;88:190-193. doi: 10.1016/j.jbiomech.2019.03.023. Epub 2019 Mar 22.
Ski jumping performance is strongly affected by wind. Flight technique optimization for maximizing jump length is a highly complex motor-control task that also depends on the wind. Pontryagin's minimum principle was used in this study to gain a better understanding on how wind influences flight technique optimization. Optimum time courses of the angle of attack α of the skis and of the body-to-ski angle β were computed for seven realistic wind scenarios on the large hill and on the flying hill. The optimum values of α were smaller at headwind, and larger at tailwind when compared to the optimum time course at calm wind. The optimum values of β were the smallest possible ones at the given flight technique constraints, except for the last part of the flight. Optimum adjustments of α increased the jump lengths between 0 and 1.8 m on the large hill, and between 0 and 6.4 m on the flying hill. Maximum jump length increases were achieved at the highest headwind speed. Even larger jump length effects can be achieved by using smaller β-angles, which might be possible in headwind conditions, but this is associated with increased problems to keep the flight stable.
跳台滑雪成绩受风力影响较大。为了最大化跳跃距离而优化飞行技术是一项高度复杂的运动控制任务，也依赖于风力。本研究运用庞特里亚金极小值原理来深入了解风力对飞行技术优化的影响。针对大型跳台和飞行跳台的七种实际风况，计算了滑雪板攻角α和人体与滑雪板夹角β的最佳时间历程。与无风时的最佳时间历程相比，逆风时的α最优值较小，顺风时的α最优值较大。在给定的飞行技术限制下，β的最优值尽可能小，除了飞行的最后一部分。在大型跳台上，α的最佳调整使跳跃距离增加了 0 到 1.8 米，在飞行跳台上，跳跃距离增加了 0 到 6.4 米。在最高风速的逆风条件下，最大跳跃长度的增加效果最为显著。通过使用更小的β角度，可以实现更大的跳跃长度效果，这在逆风条件下可能是可行的，但这会增加保持飞行稳定的问题。
