Movement economy and efficiency are regarded as important parameters for endurance performance. Whereas movement economy is used in movements where it is difficult to calculate external work rate (e.g., running), efficiency is often used in movements where the opposing forces can be measured and external work rate can be calculated (e.g., cycling, rowing). During roller skiing on a treadmill, the opposing forces can be measured. In present study we investigated the effect of gender, discipline (cross-country, biathlon and Nordic combined), level of performance (world class vs. national class) and technique (V1 and the V2 skate technique) on sub-maximal efficiency. Methods: This study include 9 male and 8 female biathletes, 22 male and 6 female cross-country skiers and 14 nordic combined skiers. All subjects were skiers of high national and international level. Sub-maximal average efficiency was calculated for a multiple set of steady state 5 min workload steps below 4 mmol/l blood lactate, for which gas exchange was measured. V1 was tested at 12% incline and the V2 at 5-8% incline, on a large treadmill. Velocity was set to each individual`s physical level in order to obtain sub-maximal measurements. External work rate was calculated using the roller friction forces, incline, subjects` mass, and velocity. Metabolic rate was calculated based on gas exchange data. Efficiency was calculated as the ratio of external work rate and metabolic rate. The results were statistically analyzed using ANOVA for repeated measures. Results: We found a highly significant difference between the V1 and V2 for both men and women and for all disciplines (17.18% vs 15.63%, p<0.001). Overall, gender differences were extremely small and not significant. We found no discipline differences. Biathlon had a smaller difference in efficiency between techniques than cross-country and Nordic combined skiers (p=0.031). World class skiers had significantly higher efficiency than national class skiers in V2 (16.28% vs 15.23%, p<0.001), and a trend in the V1 (17.58% vs 16.98, p=0.07). Furthermore, a strong inter-individual correlation was found between V1 and V2 efficiency (r=0.734, p<0.001). Discussion: Efficiency is lower during roller ski skating than in bicycling (20-25%), but it is close to speed skating (16%) and slide board skating (15%). The higher V1 efficiency might be a result of this technique being slower and relying more on concentric muscle action, as well as being more continuous in power generation, than V2. Biathlon skiers have less difference between V1 and V2 efficiency which might be a result of training and technique differences. Efficiency seems to differ between performance levels in ski skating. Also, the inter-individual correlation shows that the two skating techniques are biomechanically and/or physiologically closely related.
© Copyright 2009 14th annual Congress of the European College of Sport Science, Oslo/Norway, June 24-27, 2009, Book of Abstracts. Veröffentlicht von The Norwegian School of Sport Sciences. Alle Rechte vorbehalten. / Übersetzt mit https://www.DeepL.com/Translator