Mid Sweden University

This investigation was designed to (a) develop an individualized mechanical model for measuring aerodynamic drag (F_d) while ski racing through multiple gates, (b) estimate energy dissipation (E_d) caused by F_d and compare this to the total energy loss (E_t), and (c) investigate the relative contribution of E_d/E_t to performance during giant slalom skiing (GS). Nine elite skiers were monitored in different positions and with different wind velocities in a wind tunnel, as well as during GS and straight downhill skiing employing a Global Navigation Satellite System. On the basis of the wind tunnel measurements, a linear regression model of drag coefficient multiplied by cross-sectional area as a function of shoulder height was established for each skier (r > 0.94, all P < 0.001). Skiing velocity, F_d, E_t, and E_d per GS turn were 15–21 m/s, 20–60 N, −11 to −5 kJ, and −2.3 to −0.5 kJ, respectively. E_d/E_t ranged from ∼5% to 28% and the relationship between E_t/v_in and E_d was r = −0.12 (all NS). In conclusion, (a) F_d during alpine skiing was calculated by mechanical modeling, (b) E_d made a relatively small contribution to E_t, and (c) higher relative E_d was correlated to better performance in elite GS skiers, suggesting that reducing ski–snow friction can improve this performance.