title: Aerodynamic drag is not the major determinant of performance during giant slalom skiing at the elite level.
abstract: 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.
authors.affiliation: Department of Biomechanics, Faculty of Sport, University of Ljubljana, Ljubljana, Slovenia.
authors.forename: M
authors.initials: M
authors.lastname: Supej
authors.forename: L
authors.initials: L
authors.lastname: Saetran
authors.forename: L
authors.initials: L
authors.lastname: Oggiano
authors.forename: G
authors.initials: G
authors.lastname: Ettema
authors.forename: N
authors.initials: N
authors.lastname: Šarabon
authors.forename: B
authors.initials: B
authors.lastname: Nemec
authors.forename: H-C
authors.initials: HC
authors.lastname: Holmberg
mesh_terms: D054874:Athletic Performance / Q000502:physiology*; D001696:Biomechanical Phenomena; D004734:Energy Metabolism / Q000502:physiology; D017276:Friction; D040362:Geographic Information Systems; D006801:Humans; D016014:Linear Models; D008297:Male; D012865:Skiing / Q000502:physiology*; D012914:Snow; D013548:Sweden; D013997:Time Factors; D014919:Wind; D055815:Young Adult