The influence of body mass in cross-country skiing.

The influence of body weight on the performance in cross-country skiing has been studied by: dimensional analysis of the ratio (R) between the factors of importance to power production (VO2max, acceleration of gravity) and the braking powers, e.g., friction and air resistance; measuring the energy cost of level skiing (N = 6); comparing male world class skiers (N = 5) with less successful ones (N = 34) and female winners of the National Championships (N = 9) with non-winners (N = 9) in regard to the relationship between body weight and VO2max. The dimensional analysis revealed that R was less than unity for rather steep uphills. For level, downhill, and less steep uphill skiing, R was greater than unity. Thus, skiers who are light will be favored in steep uphill slopes, whereas heavier skiers have advantages in the other parts of the track. Energy cost per kilogram for level skiing was inversely related to the transported mass. Per unit of distance, this cost was positively related to velocity. The world class skiers displayed significantly greater VO2max than the less successful ones, regardless of the unit used. The lowest standard deviation among the world class skiers was attained when expressing VO2max as ml X min-1 X kg-2/3. The present results indicate that R will be quite close to unity and therefore the performance capability would theoretically be independent of body mass. Furthermore, VO2max is preferably expressed as ml X min-1 X kg-2/3 for cross-country skiers.