Application of Experimental Measurements in a Wind Tunnel to the Development of a Model for Aerodynamic Drag on Elite Slamo and Giant Slamo Alpine Skiers  
[PERSON]  
1 Faculty of Sport, University of Ljubljana, 1000 Ljubljana, Slovenia; [EMAIL_ADDRESS] (M.M. ); [EMAIL_ADDRESS] (J.O. )1 Faculty of Sport, University of Ljubljana, 1000 Ljubljana, Slovenia; [EMAIL_ADDRESS] (M.M. ); [EMAIL_ADDRESS] (J.O. )1 Faculty of Sport, University of Ljubljana, 1000 Ljubljana, Slovenia; [EMAIL_ADDRESS] (M.M. ); [EMAIL_ADDRESS] (J.O. )1 Faculty of Sport, University of Ljubljana, 1000 Ljubljana, Slovenia; [EMAIL_ADDRESS] (M.M. ); [EMAIL_ADDRESS] (J.O. )1 Faculty of Sport, University of Ljubljana, 1000 Ljubljana, Slovenia; [EMAIL_ADDRESS] (M.M. ); [EMAIL_ADDRESS] (J.O. )1 Faculty of Sport, University of Ljubljana, 1000 Ljubljana, Slovenia; [EMAIL_ADDRESS] (M.M. ); [EMAIL_ADDRESS] (J.O. )1 Faculty of Sport, University of Ljubljana, 1000 Ljubljana, Slovenia; [EMAIL_ADDRESS] (M.M. ); [EMAIL_ADDRESS] (J.O. )1 Faculty of Sport, University of Ljubljana, 1000 Ljubljana, Slovenia; [EMAIL_ADDRESS] (M.M. ); [EMAIL_ADDRESS] (J.O. )1 Faculty of Sport, University of Ljubljana, 1000 Ljubljana, Slovenia; [EMAIL_ADDRESS] (J.O. )1 Faculty of Sport, University of Ljubljana, 1000 Ljubljana, Slovenia; [EMAIL_ADDRESS] (J.O. )1 Faculty of Sport, University of Ljubljana, 1000 Ljubljana, Slovenia; [EMAIL_ADDRESS] (J.O. )1 Faculty of Sport, University of Ljubljana, 1000 Ljubljana, Slovenia; [EMAIL_ADDRESS] (J.O. )1 Faculty of Sport, University of Ljubljana, 1000 Ljubljana, Slovenia; [EMAIL_ADDRESS] (J.O. )1 Faculty of Sport, University of Ljubljana, 1000 Ljubljana, Slovenia; [EMAIL_ADDRESS] (J.O. )1 Faculty of Sport, University of Ljubljana, 1000 Ljubljana, Slovenia; [EMAIL_ADDRESS] (J.O. )1 Faculty of Sport, University of Ljubljana, 1000 Ljubljana, Slovenia; [EMAIL_ADDRESS] (J.O. )1 Faculty of Sport, University of Ljubljana, 1000 Ljubljana, Slovenia; [EMAIL_ADDRESS] (J.O. )1 Faculty of Sport, University of Ljubljana, 1000 Ljubljana, Slovenia; [EMAIL_ADDRESS] (J.O. )1 Faculty of Sport, University of Ljubljana, 1000 Ljubljana, Slovenia; matej. performing giant slalom is associated with 10% greater energy loss due to aerodynamic drag. Although not the primary determinant of the performance of elite giant slalom skiers, aerodynamic drag accounts, on average, for 15% (range 5-28%) of the total energy dissipated during each turn [11]. Clearly, it is important to distinguish between energy losses due to ski-snow friction and those due to aerodynamic drag, especially in connection with the technical disciplines slalom and giant slalom. The equation for aerodynamic drag (Fd) developed by [PERSON]--Fd = Cd-p-S-V2/2--incorporates four parameters: the drag coefficient (Cd), the skier's frontal cross-sectional area (S), the air density (\(\rho\)), and wind (skiing) speed (V) (Table 1). Although V is a key determinant of the magnitude of Fd, the drag can be reduced significantly by reducing Cd and S through adopting an optimal posture. In one of the first studies on Fd during alpine skiing, two subjects exhibited Cd values of 1.0-1.2 and 1.3-1.4 in an upright and semi-squatting position, respectively, and S values of 0.8-1.3 and 0.6-0.8 m\({}^{2}\) in an upright and semi-squatting position, respectively [5]. The values of these same parameters for downhill alpine skiers were considerably lower [12; 13], particularly for speed skiers, for whom Cd could be as low as 0.16 [9]. The studies performed in wind tunnels focused primarily on optimizing posture to reduce aerodynamic drag, examining not only Cd and S, but also the product Cd-S as a function of posture [10; 12; 14; 15]. Their findings clearly demonstrate that posture height and joint angles, as well as the positioning of the arms and head, all influence aerodynamic drag.