In alpine skiing, an athlete must negotiate the course by managing the production and absorption of external forces. While aerodynamic forces have been shown to be predictive of performance in some disciplines (Hebert-Losier et al., 2014), ground reaction forces (GRFs) are the primary mechanism for skiing actions. For these reasons, force output in skiers has attracted interest in both applied research (Hebert- Losier et al., 2014) and conditioning practice (Hydren et al., 2013). Logically, the amount of ground reaction forces produced during skiing is intrinsically related to the kinematic characteristics observed. That is, a turn performed at higher speeds and a tighter turn radius (i.e. radial force = velocity2/radius) will be associated with a greater GRF profile than slower and less aggressive turn tactics (assuming consistent body-weight [BW]). While force is often explained as the subsidiary variable in this equation (i.e. greater GRFs are a result of the speed and line choice), the inverse explanation holds interest for understanding performance for training athletes: Athletes who can produce greater force (and notably radial force) can similarly turn with a smaller radius while maintaining a high velocity or turn at a higher velocity with a given radius (Nakazato et al., 2011). Certainly, an enhanced capacity for force production is generally accepted as a necessary physical component for ski athletes (Hydren et al., 2013; Turnbull et al., 2009). However, while some evidence suggests advanced athletes exhibit a greater ability to produce force (Keranen et al., 2010), the relationship is likely more complicated (Supej et al., 2011). Data on the subject is rare, and often features limitations due to technology and the complex nature of collection in an alpine environment. In alpine skiing, GRFs can be measured in a variety of means, but generally: 1) directly, either assuming output via pressure insoles (Falda-Buscaiot et al., 2017) or using specialized force platforms (Nakazato et al., 2011), and 2) indirectly using video (Supej et al., 2011) or GNSS in combination with other micro-technologies (Sporri et al., 2018). Clearly, among these methods force-platforms are the gold-standard in measuring kinetic activity, but the challenging alpine environment and difficulty integrating technology with skiing material has substantially limited studies utilizing this method. Technological limitations have complicated data capture capabilities and resulted in somewhat invasive designs (e.g. increased clip-in height, weight and modifications to the rigidity of the ski) that inevitably degrade measurement validity. A recent system presented by Falda-Buscaiot et al. (2016) shows promise by addressing several of the confounding factors featured in traditional devices. Using such technology in high-level skiing practice could feasibly provide a deeper understanding of athlete force production during both biomechanical and strength and conditioning practice. Using validated force plates (Falda-Buscaiot et al., 2016) we aimed to (i) compute magnitudes and balance of force produced on a giant slalom course, (ii) test the relationship between force output parameters and kinematic parameters, and (iii) test the relationship between course performance and force measures.
© Copyright 2020 Science and Skiing VIII. Book of the 8th International Congress on Science and Skiing. Julkaistu Tekijä University of Jyväskylä; Vuokatti Sports Technology Unit of the Faculty of Sport and Health Sciences of the University of Jyväskylä. Kaikki oikeudet pidätetään. / Kääntänyt https://www.DeepL.com/Translator