Optimal [??][O.sub.2max]-to-mass ratio for predicting 15 km performance among elite male cross-country skiers

The aim of this study was 1) to validate the 0.5 body-mass exponent for maximal oxygen uptake ([??][O.sub.2max]) as the optimal predictor of performance in a 15 km classical-technique skiing competition among elite male cross-country skiers and 2) to evaluate the influence of distance covered on the body-mass exponent for [??][O.sub.2max] among elite male skiers. Twenty-four elite male skiers (age: 21.4 ± 3.3 years [mean ± standard deviation]) completed an incremental treadmill roller-skiing test to determine their [??][O.sub.2max]. Performance data were collected from a 15 km classical technique cross-country skiing competition performed on a 5 km course. Power-function modeling (ie, an allometric scaling approach) was used to establish the optimal body-mass exponent for [??][O.sub.2max] to predict the skiing performance. The optimal power-function models were found to be race speed = 8.83 x [([??][O.sub.2max] [m.sup.-0.53]).sup.0.66] and lap speed = 5.89 x [([??][O.sub.2max] [m.sup.-(0-49 + 0.018lap)]).sup.0-43][e.sup.0.010age], which explained 69% and 81% of the variance in skiing speed, respectively. All the variables contributed to the models. Based on the validation results, it may be recommended that [??][O.sub.2max] divided by the square root of body mass (mL x [min.sup.-1] x [kg.sup.-0.5]) should be used when elite male skiers' performance capability in 15 km classical-technique races is evaluated. Moreover, the body-mass exponent for [??][O.sub.2max] was demonstrated to be influenced by the distance covered, indicating that heavier skiers have a more pronounced positive pacing profile (ie, race speed gradually decreasing throughout the race) compared to that of lighter skiers. Keywords: allometric scaling, maximal oxygen uptake, cross-country skiing, pacing