PhD N.B. Novikova¹
A.N. Belyova¹
I.G. Ivanova¹
PhD N.B. Kotelevskaya^1
1Saint-Petersburg scientific-research institute for physical culture, St. Petersburg

Keywords: ski racers, video analysis, alternating two-step classic stroke, angular characteristics.

Introduction. The alternating two-step classical course (PSHX) is a natural way of movement, and it is from this that the training in the technique of ski moves begins at the initial stage of preparation. To improve the technique of technical training, it is necessary to study the biomechanical characteristics of ski runs [1].
The purpose of the study is to determine the age and gender characteristics of the kinematics of the SHC.
Methodology and organization of the study. Video shooting of the skiing technique was carried out on the ascents of distances of 5 and 10 km for boys and girls at the Russian Championship on 16.02.2022 and 10 and 15 km for women and men at the World Cup stage on 27.02.2022. The steepness of the ascent section in both cases was 6 °, the weather was stable, the snow temperature – -2.1 –
-2.3 ° C. The resulting videos were processed in the Dartfish Pro program, and the kinematic indicators of the best 50 young and 30 adult athletes at each distance were determined.
The results of the study and their discussion. The technique of men and women did not have significant differences in most indicators, while the features of performing movements by boys and girls that reduce the effectiveness of movements were determined. During the lunge, the girls do not bend the leg sufficiently in the knee and ankle joints, which leads to a lag in the projection of the center of mass and requires additional muscle effort to move the body weight forward during a single-support slide. At the moment of stopping the ski, the angles in the knee and hip joints of boys and girls were significantly less than those of adult athletes, which leads to a shift in the projection of the center of mass back relative to the support. At the moment of squatting, girls and boys tilt the lower leg more than adult athletes, and the angles in the knee and hip joints do not have significant differences. Young racers in this phase actively shift their body weight forward, which is an important criterion for the effectiveness of the technique. The angular characteristics of the end of repulsion in all groups have no significant differences.
Conclusion. The analysis of the angular characteristics of the alternating two-step stroke showed that the main differences in the girls' technique are in performing a wide lunge, greater bending of the leg at the knee joint and tilting of the trunk at the moment of stopping the ski. The main technical flaw of the young men is the insufficient extension of the supporting leg in the knee and hip joints at the time of stopping the ski. The approximation of the projection of the center of gravity to the foot of the supporting leg in a sliding step will increase the efficiency of the course by reducing the effort to maintain balance, reduce the amplitude and duration of squatting in girls and boys. The kinematic characteristics of the alternating two-step ski course of the world's strongest athletes can be a guide in the technical training of young ski racers.

Literature

1. Reutskaya E.A. Technical training of young ski racers at the stages of long-term training: methodological recommendations / E.A. Reutskaya, T.V. Poltoratskaya. – Omsk: YUNZ, 2020. - 160 S. P.F. Lesgaft. – 2021. – Vol. 191. – No. 1. – pp. 427-436.