A LONGITUDINAL STUDY OF THE TAKE-OFF AND TRANSITION PHASE IN SKI-JUMPING AT INTERSPORTTOURNEE INNSBRUCK 1992-1994

Abstract

The ski-jump is realized in a very variable external conditions influenced by differences in the jumping hill constructions, approach velocities, surfaces (snow, mat, ceramic) and climatic conditions. The take-off phase is also determined by many other factors relating to the structure of movement abilities of individuals and their specific personal patterns of the take-off. The body dimensions can also influence the pattern of the take-off in the last period (it is characterized e.g. by a very low values of Rohrer’s Index, RI = 1.07 - 1.15 by the best jumpers). The change of flight position to the "V" style in the last 2-3 years can also be the factor which could influence the realization of the take-of f . The previous suggestions bring about following questions: - What does the present pattern of the take-off and transition phase look like ? - Are there any differences in the pattern of the take-off and transition phase in the last three-year period ? The event of the World Cup Intersporttournee Innsbruck is a very suitable opportunity to solve this problem. Here the set of all the best world athletes regularly take part on the same date (January 4) each year. During the last three years 1992, 1993, and 1994 the take-off and transition phase being taped at the same position of the cameras in the terraine. By using of the programme package The System of Kinematic Analyses of Ski-jumping, which was developed in our Laboratory, the 2-D analyses were realized for both observed phases. The set of angle and speed parameters describe the anal zed phases. From the sets of all athletes in 't1he rounds (n = 50 - 60) the sets of the best present jumpers (n = 15) were selected according to the length of jump. The statistical analyses were realized for the whole set of the lSt round athletes (correlation and factor analyses) and for the selected sets of the best jumpers. The comparison of the results from different periods of the complete and selected sets of athletes was the starting point for the solution of our problem.