CORRELATION OF SOME KINEMATIC PARAMETERS WITH COMPETITIVE SUCCESS OF SKIJUMPERS AT THE 1994 WORLD CHAMPIONSHIP IN SKI-FLIGHTS IN PLANICA

Abstract

The purpose of this research was to evaluate selected biomechanical parameters and find the level of correlation to competitive success at the 1994Planica ski-flights competition. The subject sample comprised of 28 ski-jumpers. They were divided into three qualitative groups; B - best, M - medium, L - low, according to their success measured by the length of the jump. The flight phase was measured for both official jumps at two points. The first was 8 m beyond the edge of the take-off table and the second 78 m beyond. The data on the kinematic parameters were obtained with the 3D video analysis system CONSPORT. One-way analysis of variance was used to test the differences between the groups and correlation analysis to test the tie with the jump length. The results of the analysis of variance showed statistically significant differences (p < 0.05) between the "quality-groups" in the flight elevation angle in the middle part of the flight. Better jumpers flew at a smaller angle and were more inclined forward during flight. They had a smaller angle between the "body-bow-line" (line joining the shoulder and ankle joint) and the skies in the XY plane. Similar tendencies were also found for the other two angles, which are supposed to be indicators of aerodynamic efficiency from the viewpoint of the horizontal component of air drag. A significant correlation(p< 0.05) was therefore found of the angle between the trunk and the skies with the angle between the "body-bow-line" and the horizontal. A significant factor for length of the jump was also the angle between the skies in the XZ plane. Better jumpers had a slightly greater angle between the skies (M=25.3 degrees)in the middle part of the flight and were also more extended in the hips (M = 175degrees).The results therefore mainly affirm the theoretically defined tendencies of the ski-flights technique and fully conform to findings of flight analysis performed at the World Cup competition in Planica (K= 120 m) in the season 1992/93.