INTRODUCTION: The present study was undertaken to compare the double poling skill between the following two groups of skiers by means of cinematographic-analysis: (1) skiers ranked in high places during the Nordic World Ski Championships Sapporo, February 2007, and (2) Japanese cross-country skiers. The study was aimed at obtaining data that would contribute to improving the performance of Japanese skiers in competition games. METHOD: The subjects of this study were six skiers ranked at top six positions in the Qualification and Final Games of Male Sprinting and two Japanese skiers. During the qualification game, three Video cameras were set at a point one km from the start (the flat area immediately before the finish). Using these video cameras, double poling motions were pictured at a rate of 120 f/sec from anterior and lateral sides, for subsequent motion analysis by the DLT method. RESULTS: The figure shows changes in elbow joint angle during double poling. Two patterns of change in elbow angle were identifled: Type 1: After the poles leave the ground, the arms are swung forwards, while bending the elbow. Then, keeping the elbow bent, the poles touch the ground. Type 2: The angle of elbow becomes minimal after the poles touch the ground. In Type 1 cases, the skiing speed was higher for skiers with higher pitches. In Type 2 cases, the skiing speed was higher for skiers with larger strides. The angler velocity of the shoulder joint bending during the period from the pole-touching point to the pole-leaving point was greater for Type 2 cases. The maximal angle of hip joint during the period from the pole-leaving point to the pole-touching point was greater for high-ranked skiers than for Japanese skiers. DISCUSSION: With Type 1 technique, the skiing speed may be elevated if the pitch can be increased by reducing the moment of inertia at the arm. On the other hand with Type 2 technique, the skiing speed will be favourably affected if there is adequate time for full exertion of muscle power during the pole-touching phase and the stride can be lengthened. What is needed for Japanese skiers is to learn the characteristics of Type 1 and 2 techniques and to select one of them, taking into account the features of their physical strength, etc.? With each technique, it seems essential that the upper half of the body is extended forward when the arms are swung forward.
© Copyright 2007 4th International Congress on Science and Skiing. Julkaistu Tekijä University of Salzburg. Kaikki oikeudet pidätetään. / Kääntänyt https://www.DeepL.com/Translator