Kinematic determinants and physiological response of cross-country skiing at maximal speed.

PURPOSE The scope of the study was to a) transfer the maximal anaerobic running test (MART) to a treadmill-based cross-country roller skiing test protocol for skating and classic style, b) analyze the development and determinants of kinematic and physiological parameters from submaximal to maximal skiing speeds, c) analyze the effects of fatigue on skiing technique, and d) test the hypotheses that maximal skiing speed is related to cycle length and that the fastest skiers show shorter thrust combined with longer swing phases. METHODS Up to 24 elite skiers performed MART tests in double poling, diagonal stride and V2 skating, with roller skis on a treadmill. Anthropometrics, blood lactate, HR, and kinematics were determined. RESULTS When compared with former studies, faster skiing speeds of up to 34% were reported. Skiers improved speed by increasing cycle rate while trying to maintain cycle length. In the diagonal stride and V2 skating at maximal skiing speeds, skiers used contrary technical strategies to maintain the speed, whereas in double poling, a tendency toward an optimum in cycle length and cycle rate was established. Duration for the pole thrusts was around 180 ms for V2 skating and 210 ms for double poling. Highest relation to performance was found for the duration of the swing phases of arms and legs. CONCLUSIONS The increase in skiing speed and cycle length, compared with former studies and the positive relation between swing phase duration, stresses the importance of effective thrust phases within a short period. Therefore, it is recommended to increase the proportion of training aimed at the improvement of specific explosive strength and maximal power to increase the impulse of force.