Department of Physical Performance, Norwegian School of Sport Sciences, Oslo 0806, Norway.
Sensors (Basel). 2013 Aug 2;13(8):9821-35. doi: 10.3390/s130809821.
In alpine ski racing the relationships between skier kinetics and kinematics and their effect on performance and injury-related aspects are not well understood. There is currently no validated system to determine all external forces simultaneously acting on skiers, particularly under race conditions and throughout entire races. To address the problem, this study proposes and assesses a method for determining skier kinetics with a single lightweight differential global navigation satellite system (dGNSS). The dGNSS kinetic method was compared to a reference system for six skiers and two turns each. The pattern differences obtained between the measurement systems (offset ± SD) were -26 ± 152 N for the ground reaction force, 1 ± 96 N for ski friction and -6 ± 6 N for the air drag force. The differences between turn means were small. The error pattern within the dGNSS kinetic method was highly repeatable and precision was therefore good (SD within system: 63 N ground reaction force, 42 N friction force and 7 N air drag force) allowing instantaneous relative comparisons and identification of discriminative meaningful changes. The method is therefore highly valid in assessing relative differences between skiers in the same turn, as well as turn means between different turns. The system is suitable to measure large capture volumes under race conditions.
在高山滑雪比赛中，滑雪者的运动学和动力学之间的关系及其对表现和与损伤相关的方面的影响还没有被很好地理解。目前还没有一个经过验证的系统可以同时确定所有作用在滑雪者身上的外力，特别是在比赛条件下和整个比赛过程中。为了解决这个问题，本研究提出并评估了一种使用单个轻型差分全球导航卫星系统(dGNSS)确定滑雪者动力学的方法。dGNSS 动力学方法与参考系统进行了比较，参考系统对六名滑雪者和两个转弯进行了测量。测量系统之间的模式差异（偏差±SD）为：地面反作用力为-26±152 N，滑雪摩擦力为 1±96 N，空气阻力为-6±6 N。转弯平均值之间的差异很小。dGNSS 动力学方法内的误差模式高度可重复，因此精度很好（系统内的标准差：地面反作用力 63 N，摩擦力 42 N，空气阻力 7 N），允许进行即时的相对比较和确定有区别意义的变化。因此，该方法非常适合评估同一转弯中不同滑雪者之间的相对差异，以及不同转弯之间的转弯平均值。该系统适用于在比赛条件下测量大的捕获体积。
