INTRODUCTION: A simple three-dimensional multibody dynamic model of a cross-country skier is developed and presented where a single propulsion phase is modeled to obtain the propulsive forces exerted by the skier. After simulating the technique, it will be tested if the calculated resultant forces are in agreement with those measured in the field. METHOD: The movements of certain key points on the body of the skier and real propulsion forces of a professional athlete performing the skating technique without poles were acquired using the Vicon System MX with 37 markers for the case of the skier's movement and an in-house forces measurement binding system for the case of the forces (Ohtonen et al. 2013). Then, applying the augmented formulation of the Lagrange's equations, and imposing a set of simplification to the leg joints and movement of the ski, the multibody model of the lower limb of the skier was constructed in MatLab, Fintelmant et al. (2011) and Bruzzo(2012). RESULTS: The simulated and measured key points on the leg and resultant force are presented in figures 1 and 2 respectively. DISCUSSION & CONCLUSION: Two important aspects can be derived from this study. Firstly, the closeness of the measured and simulated positions of the key markers selected on the leg of the skier demonstrate the possibility of using the simplifications of the lower limb of the skier to conduct this kind of study, and secondly, the simulated force obtained shows a good agreement with the measured one. As the propulsive force is a component of the resultant forces, this can be easily obtained. Having a simulation tool can serve as a mean to evaluate the performance of the athletes. The possibility of using simplified multibody models to simulate the human movement was demonstrated, and more specifically for a winter sport such as cross-country skiing. --- The hosting University of Jyväskylä is planning to publish conference proceedings "Science and Nordic Skiing III". In case you are interested in this publication please contact the editors (Anni Hakkarainen anni.s.j.hakkarainen@jyu.fi) to become registered for the book.
© Copyright 2015 3rd International Congress on Science and Nordic Skiing - ICSNS 2015. 5-8 June 2015, Vuokatti, Finland. Published by University of Jyväskylä; University of Salzburg. All rights reserved.