Application of experimental measurements in a wind tunnel to the development of a model for aerodynamic drag on elite slalom and giant slalom alpine skiers

Majerič, Matej (author), Verdel, Nina (author), Ogrin, Jan (author), Holmberg, Hans-Christer (author), Supej, Matej (author)

Aerodynamic drag is a major cause of energy losses during alpine ski racing. Here we developed two models for monitoring the aerodynamic drag on elite alpine skiers in the technical disciplines. While 10 skiers assumed standard positions (high, middle, tuck) with exposure to different wind speeds (40, 60, and 80 km/h) in a wind tunnel, aerodynamic drag was assessed with a force plate, shoulder height with video-based kinematics, and cross-sectional area with interactive image segmentation. The two regression models developed had 3.9–7.7% coefficients of variation and 4.5–16.5% relative limits of agreement. The first was based on the product of the coefficient of aerodynamic drag and cross-sectional area (C$_d$·S) and the second on the coefficient of aerodynamic drag C$_d$ and normalized cross-sectional area of the skier S$_n$, both expressed as a function of normalized shoulder height (h$_n$). In addition, normative values for C$_d$ (0.75 ± 0.09–1.17 ± 0.09), S$_n$ (0.51 ± 0.03–0.99 ± 0.05), h$_n$ (0.48 ± 0.03–0.79 ± 0.02), and C$_d$·S (0.23 ± 0.03–0.66 ± 0.09 m$^2$) were determined for the three different positions and wind speeds. Since the uncertainty in the determination of energy losses due to aerodynamic drag relative to total energy loss with these models is expected to be <2.5%, they provide a valuable tool for analysis of skiing performance.

• Language: English
• Keywords: sport, biomechanics, mechanical modelling, energy, dissipation, energy loss, coefficient of aerodynamic drag, cross-sectional area, performance, GNSS, GPS
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FŠ - Faculty of Sport
• Publication status: Published
• Publication version: Version of Record
• Year: 2022
• Number of pages: 11 str.
• Numbering: Vol. 12, iss. 2, art. 902
• PID: 20.500.12556/RUL-137125
• UDC: 796.9
• ISSN on article: 2076-3417
• DOI: 10.3390/app12020902
• COBISS.SI-ID: 93746179
• Publication date in RUL: 01.06.2022

Record is a part of a journal

• Title: Applied sciences
• Shortened title: Appl. sci.
• Publisher: MDPI
• ISSN: 2076-3417
• COBISS.SI-ID: 522979353

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.
• Licensing start date: 17.01.2022

Secondary language

• Language: Slovenian
• Keywords: šport, biomehanika, mehansko modeliranje, energija, disipacija, izguba energije, površina preseka, izvedba, alpsko smučanje, slalom, veleslalom

Projects

• Funder: ARRS - Slovenian Research Agency
• Project number: P5-0147
• Name: Kineziologija monostrukturnih, polistrukturnih in konvencionalnih športov