INTRODUCTION: Several factors have contributed in the last few years to increase the importance of double poling (DP) technique in cross country ski. Evaluation and training of upper body power is usually performed by means of a traditional strength training apparatus even if the movements performed on this equipment are however quite different from the specific motion, The Nordic Ski Ergometer developed by CeBiSM has already demonstrate a good correlation between the average power measured with the ergometer and the performance in ski specific action (Bortolan, 2007). To investigate thoroughly the specificity of this ergometer the power measured by the ergometer during an multi load test has been compared with the power exerted during a double poling incremental test on a treadmill. METHOD: Data of 29 well trained athletes (18 male and 11 female) collected during the evaluation test program of Italian National Team were analysed. The measurements on the treadmill (RSki) were conducted skiing at a constant inclination of 3° for male and 2" for female whereas the velocity increases of 0.5km/h every 30s. The poling power on the treadmill has been calculated multiplying poling force, acquired by the load cell, by the longitudinal poling velocity (PV) measured by kinematic data acquisition System (Qualisys). In the same testing session the athletes were requested to performed 12 repetition on the Nordic Ski Ergometer (NoSkE) at maximal effort at 5 selected load. The power has been calculated as the product of traction force by the unwinding velocity of the cable. The power and the force exerted at the last step of the incremental test on the treadmill and on the ergometer were then compared and the correlation was examined by calculating regression coefficient. RESULTS and DISCUSSION: Mean power for RSki was 810±73W for male and 449+43W for female, and was statistically different from the NoSkE power (M: 853±123W; F: 391±78W). There are no statistic difference for force (M: RSki 138±14N; NoSkE:140±22N; F: RSki 77±11N; NoSkE: 84±8N). An high correlation between Roller SW test and NoSkE test was found for power (R=0.96; p<0.001) and for force (R=0.94; p<0.001). No difference in poling time (PT) was found by a paired samples Student test while significant differences were found for poling velocity (PV) and cycle time (CT). Having found that the same force is exerted in the comparable poling time we can hypothesize that a similar effort is request to perform the poling Imitation. The lower poling velocity (PV) of NoSkE can suggest that a better similarity of the poling power can be reached imposing an higher velocity of the ergometer. CONCLUSION: High correlations found for power and force further support the specificity of Nordic Ski Ergometer to assess the athletes performance in double poling technique. The high rapidity of recovery phase in double poling technique remains however the main problem to solve in order to develop an even more specific double poling ergometer for testing and training cross-country skiers.
© Copyright 2007 4th International Congress on Science and Skiing. Julkaistu Tekijä University of Salzburg. Kaikki oikeudet pidätetään. / Kääntänyt https://www.DeepL.com/Translator