INTRODUCTION: The effect of movement frequency has been extensively studied in endurance Sports like cycling. It is believed that frequency affects both efficiency and performance in endurance Sports. The purpose of the present study was to examine the effect of frequency on efficiency at different work rates and on performance using the G3 skating technique. METHOD: Eight elite cross-country skiers 22.5 years old, 74.5 kg with 68.4 ml/kg/min in movement specific VO2peak, participated in this study. On three occasions in the lab, using three different frequencies, subjects performed three sub-maximal 5 min work periods and a performance test. The three frequencies were freely chosen (FCF), freely chosen -10 strokes per minute (FCF-10) and freely chosen +10 strokes per minute (FCF+10). The three submaximal work rates were obtained at 10, 13 and 16 km/h at a 5% incline. The performance lest was time to exhaustion at 5% incline and 20 km/h (time range 5-10 min). Gross efficiency was calculated by dividing external work rate with the metabolic rate. External work rate was calculated taking into account both work against gravity and frictional rolling forces. Metabolic rate was calculated using gas exchange and blood lactate values. RESULTS: Mean efficiency results are shown in Fig. 1. There were no physiological effects of frequency at any of the sub-maximal work rates (10, 13 and 16 km/h). At the performance test (20 km/h) there were a significant lower gross efficiency at the FCF+10 condition compared to the FCF-10 condition (p=0.02). Also, in the performance test there was a 36 % shorter time to exhaustion for the FCF+10 condition compared to both the FCF condition (p=0.01) and the FCF-10 condition (p<0.01). DISCUSSION: The FCF gave the best or similar performance and efficiency as the lower and higher frequencies. Thus, cross-country skiers seem to self-optimize choice of frequency during G3 skating. CONCLUSION: Choice of frequency in cross-country skiers seems to be self-optimized during G3 skating both for energy saving and performance.
© 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.