Calculation of mechanical energy in cross country skiing

Abstract: Cross country skiing is considered to be one of the most demanding sports in terms of endurance. Therefore the skiers are attractive subjects for physiological and biomechanical research whose interest has increased a lot during the 21 stcentury. The results are used to improve the mechanical knowledge about the body and to improve the capacity and technique for the competitors. The aim with this study is to implement a method for mechanical energy calculation in cross country skiing. This is based on data from 15 skiers using the double poling technique, where the potential, rotational and translational energies are calculated. The measurements are made in a lab using a treadmill with stepwise increased velocity. The system used is Vicon MX where the skiers wear re- ective markers, whose positions is calculated from data from infra-red light cameras. The positions of the joint centres are calculated used as input data to the program. Joint centres and marker data divide the body into segments where the energies of each segment are calculated and possible to sum up for the whole body. The results are examples of obtainable data from the model. It is possible to compare chosen subjects' total mechanical energy but also the energies and segments separately. The results can be used to analyse the dierent techniques to improve the capacity of the competitors.