Biomechanical Analysis of Chinese Male Cross-Country Skiers with Double Poling Technique on Uphill Terrain during Long Distance Classical Race / 医用生物力学

ABSTRACT

Objective By making biomechanical analysis of double poling (DP) technique on uphill terrain used by Chinese male cross-country (XC) skiers, to characterize biomechanical differences in DP for skiers at different levels, and determine the influence from motion techniques of skiers on their sports performance. Methods Twenty-four male XC skiers who participated in the 15 km classical race at the Beishan ski resort in Jilin, China, on Sept. 11-12, 2019 were selected in this study. On the basis of their race performance, they were divided into faster skiing group (n=12) and slower skiing group (n=12). The kinematic variables of the skiers were obtained by three-dimensional (3D) shooting, and the differences in cycle characteristics, action phases and key technique variables for skiers in two groups were analyzed. Results Faster skiers had a faster DP velocity. There was a positive correlation between swing distance and velocity. The swing distance was positively correlated with average angular velocity of elbow extension in poling phase, average angular velocity of shoulder extension in swing phase, and range of motion (ROM) of shoulder abduction. The swing distance was negatively correlated with extension of the elbow in poling phase. All the above variables showed statistical differences between faster and slower skiers. Conclusions For a long distance competition, the difference in DP velocity on uphill terrain was mainly casued by the difference in swing distance, which originated from the swing phase. Faster skier had a longer swing distance. The differences in the swing distance came mainly from the shoulder and elbow joints. Therefore, slower XC skiers in China should strengthen muscle strength of the upper limbs, especially the shoulder and elbow joint strength. More forward body leaning and larger hip and knee flexion angle at pole plant might help the skier to cover more distance.