INTRODUCTION: In cross-country ski-skating, two skating techniques (V1 and V2) are used on moderate uphill terrain. V1 skating is typically used for steeper climbing while V2 is a higher speed technique for flat and rolling terrain. In recent years, there has been some emphasis on using V2 technique on steeper uphills. Comparisons have been made of V1 and V2 under controlled laboratory conditions with rollerskiing on a treadmill (Kvamme et al., 2005, Smith et al. 2009) but on-snow comparisons of the techniques during racing have not been made. This paper is a case study of two elite skiers during a World Cup race. Kinematic comparisons of their use of V1 and V2 skating techniques were made at a site during the race where it was expected that skiers would be transitioning from V2 to V1 technique. METHODS: Kinematic data were collected during the men's FIS world cup 15 km (3 x 5 km laps) at Beitostolen, Norway in November, 2007. This was a free technique (skating), individual start race. Five cameras were used videotaping the athletes in the lower portion of a long uphill where the slope was about 6.5°. The DLT method was implemented in MatLab to determine full-body 3D position-time data. Digitizing of landmarks was completed at 25 Hz. From the 3D data, center of mass and other kinematic characteristics were determined. Each skier used V2 technique through the analysis zone on the first lap of the race and V1 technique through the zone on the third lap of the race. This provided opportunity to compare the techniques under similar race conditions. RESULTS & DISCUSSION: The two skiers finished the 15 km race in 37:15 and 37:57. Their first and third lap times (5 km) were 12:00 vs 12:43 and 12:29 vs 12:34. Skating speeds through the analysis zone were slower using V1 in the third lap: 4.1 ±0.1 m/s with V2 vs 3.9 ± 0.1 m/s with V1. In Figure 1 the pattern of speed fluctuation during skating cycles is illustrated. In V2 with two poling phases there is greater fluctuation of speed during a cycle. But V2 is spread over a longer time: Cycle frequencies for V2 were 0.61 + 0.07 Hz and 0.95 ± 0.08 Hz for V1. Cycle length was considerably greater with V2 than V1: 6.9 ± 1.0m vs 4.1 ±0.2 m. Ski angles graphed in Figure 2 show the wider orientation observed for V1. This contributes to cycle length reduction for V1 skating. CONCLUSION: A change from V2 to V1 skating on moderate uphill during competition resulted in reduced speed and cycle length. Whether this was due to technique choice or to fatigue is unknown.
© Copyright 2010 Book of Abstracts. 5th International Congress on Science and Skiing, Dec. 14 - 19, 2010, St. Christoph am Arlberg. Veröffentlicht von University of Salzburg, Interfakultärer Fachbereich Sport- und Bewegungswissenschaft/USI. Alle Rechte vorbehalten. / Übersetzt mit https://www.DeepL.com/Translator