OFFSET SKATING CHARACTERISTICS OF WORLD CUP LEVEL CROSS-COUNTRY SKIERS

Abstract

The cross-country ski skating techniques have been evolving steadily over the past several years. Previous kinematic and temporal studies conducted by Smith, McNitt-Gray, & Nelson (1988); Smith & Nelson (1988); Smith, Nelson, Feldrnan, & Rankinen (1989); and McPherson (1991) have documented this evolution. A kinematic and temporal study was conducted during the 1994 Men's World Cup Cross-Country Ski Relay competition in Thunder Bay. The study was used to develop a current kinematic and temporal profile of the World Cup level competitors based on a multiple correlation and regression analysis of selected variables. The Peak 2D Motion Analysis System was used to digitize video footage of 24 competitors offset skating on a 9 degree slope. A significant positive relationship was found between the dependent variable cycle velocity and cycle length (ec.01,2-tailed). Further significant positive relationships (ec.05, 2-tailed) were found between the dependent variable race velocity and cycle velocity, and percentage of cycle time skating on the downhill leg. In addition there were other significant correlations found among the selected variables. Cycle length increased as the uphill pole angle at pole plant decreased (ec.05, 2-tailed), and the cycle velocity increased (ec.01, 2-tailed). Cycle time decreased as the percentage of the cycle time skating on the uphill leg and the cycle velocity increased (e<.05,2-tailed). The percentage of the cycle skating on the downhill ski increased as the percentage of the time skating on the uphill ski and the uphill pole angle decreased (ec.05, 2- tailed). Selected independent variables cycle length, cycle velocity, and percentage of cycle skating on the downhill ski were used to build a direct regression equation to predict race velocity. Stepwise regression showed that cycle velocity and percentage of the cycle skating could be excluded from the equation. Cycle length was the most important variable for predicting race velocity. The results of this study have important implications for athletes who wish to offset skate at a high velocity on a steep slope. They must learn to skate with a longer cycle length of approximately 6 m, shorter cycle time of approximately 1.0 second, more balanced skate off each leg and an uphill pole angled back when planted, but close to vertical (7 degrees).