Abstract

Alpine ski racing is a challenging sport in an outdoor environment. The difference among top level World Cup (WC) skiers is often hundredths of a second in a race. However, it has been shown that time differences in shorter sections along the course can vary by 10% among the fastest skiers (Supej & Cernigoj, 2006). Consequently, even at the highest level, skiers can significantly improve their sectional performance. Energy dissipation is one of the crucial performance predicting parameters (Reid et al., 2009; Supej, 2008; Supej, Kipp, & Holmberg, 2010). The main factors in energy dissipation are air drag and ski-snow friction. A variety of studies have investigated ski-snow friction (Colbeck, 1994; Federolf et al., 2008). On the other hand, the air drag, which to our knowledge cannot be directly measured during skiing, was relatively seldom investigated in the context of technical disciplines in alpine skiing. The only available study related to technical disciplines proposed a quadratic model between body posture and the air-drag coefficient multiplied by the skier’s cross-sectional area (Barelle, Ruby, & Tavernier, 2004). However, as described in the study, the model does not permit a precise comparison between two skiers and has an accuracy of 17% for upright postures. Therefore, the aim of this study was to study further the air drag in technical disciplines and explore methodology for examining air drag among elite ski racers. Einleitung