INTRODUCTION: Alpine skiing performance depends on a complex interaction between forces, energy dissipations, inter-dependency of turns, speed, and trajectories. Extensive studies have been done to understand the biomechanics of skiing. However, the necessary complexity of study approaches often limits the transferability of the testing procedures to field use. The present study investigates the effectiveness of using GNSS-RTK technology in evaluating the performance of alpine skiers. METHODS: Ten regional level skiers (GS FIS points: 80.5±33.8) performed a maximal speed single run on a 31-gate GS course. Skiers` trajectory and the position of the gates were acquired using a u-blox ZED-F9P GNSS-RTK device connected to an Android smartphone to enable the NTRIP correction and to record the position at 10Hz. The data were analyzed with Matlab. Velocity (V), acceleration (a) and mechanical energy differences (dEm) were analyzed by splitting the curves into five sectors starting from the gate passages. RESULTS: The race time (RT) calculated by the GNSS system has always been longer than that measured with photocells (TGNSS -TChrono: 0.343±0.057 s; p<0.0001). Significant correlations were found between RT and GS FIS points (p=0.03), race velocity (p<0.0001), and path length (p=0.008). Different speeds (p<0.0001), and dEm (p<0.0001) were found for the different sections of the curves. Significant correlations were found between race time and the accelerations only for sections 3, 4, and 5 of the curves. DISCUSSION/CONCLUSION: Differences in race time may be due to the forward body jump at the start. Our results confirm the importance of the relationship between path length and speed- acceleration- and energy-related factors in race performance. The differences in these parameters over the different parts of the curve underline the advantage of splitting the curve into separate parts. Although more in-depth analyzes should be done, GNSS-RTK technology, given its low cost and adequacy in measuring relevant technical aspects, could be used on a large scale during training sessions in alpine skiing.
© Copyright 2023 9th International Congress on Science and Skiing, March 18 - 22, 2023, Saalbach-Hinterglemm, Austria. Julkaistu Tekijä University of Salzburg. Kaikki oikeudet pidätetään. / Kääntänyt https://www.DeepL.com/Translator