ANGULAR MOMENTUM IN JUMPS WITH ROTATIONS ON THE LONGITUDINAL AXIS IN FIGURE SKATING -3D-ANALYSES AND COMPUTER SIMULATION

Abstract

INTRODUCTION -In analyses of athletic technique in figure skating primarily jumps with tripie or four-time rotations on the longitudinal axis are considered The quality of these jumps is essentially influenced by vertical momentum and angular momentum. While vertical momentum can be obtained without problems from flight parameters the calculation of angular momentum does represent a much more complicated problem. The task is to optimise vertical and angular momentum and to answer the question for reasons causing that the longitudinal axis is tilted during flight. This is important since a slightly tilled position of this axis can cause a fall in figure skating. Analyses of errors therefore mostly concentrate on the identification of reasons for this tilted position during flight already in the take-off. Therefore 3D monitoring only is insufficient for recommendations on sports techniques but additional 3D calculations (e.g. calculation and three-dimensional presentation of angular momentum) have to be performed. METHODS -A procedure for a threedimensional presentation of angular momentum as vector is presented. Using this procedure reasons for errors can be determined and general orientations for sport technical models can be characterised. Another procedure offers the opportunity to quantify the partial contribution of individual parts of the body in producing angular momentum. To determine the efficient use of the produced angular momentum 3D computer simulation is applied RESULTS 1. The influence of the angle between longitudinal axis and direction of angular momentum on the efficient use of the produced angular momentum is determined as a result of computer simulation 2 The influence of movements of individual parts of the body on the production of the total angular momentum as a reason for tilting the longitudinal axis during flight is studied. 3. We study practical applications in sports practice to present conclusions for the training of sports technique We give recommendations for individual solutions concerning sports technique res. general models to optimise sports technique of the most complicated technical elements. Using the example of the triple Axel, the most complicated triple jump in figure skating, we present opportunities for an interpretation of our results in sports practice.