INTRODUCTION: Earlier studies (Supej et al., 2005) have compared energy dissipation (EDISS) with ski turn radius. There is reason to believe, however, that EDISS will follow the center of mass turn radius (RCOM) more closely. The aim of this study is to compare the relationships between the turn radius of the outer ski (RSKI), RCOM. and EDISS. METHOD: By means of motion analysis, using 4 panning video cameras and multiple calibration points, the kinematics of 5 skiers of the Norwegian men's Europa Cup team were captured during two entire slalom turn cycles. On the basis of these kinematic data, RSKI and RCOM were calculated and plotted over a whole turn cycle (Figure 1 shows one example of them). Secondly, instantaneous energy dissipation as suggested by Supej et al. (2005) of the 5 individuals for both turns were calculated and plotted against RSKI and RCOM (Figure 2). DISCUSSION: In examining Figure 1 it is apparent that the time course of EDISS follows that of RCOM more closely than that of RSKI- Especially RCOM is not decreasing to the smallest radii, before EDISS increases substantially. There are periods of time, at the beginning and the end of the turn, (highlighted by the green frames), where EDISS is low despite a sharply turning ski. These areas can as well be identified in Figure 2, where the red circles representing these RSKI at low EDISS are dominantly represented in the zooming frame, Due to the increased EDISS during the sharpest turning phase of CQM, RCOM are underrepresented there. CONCLUSION: Both Figures emphasize, that EDISS is temporally strongly related to RCOM and that EDISS is a better indicator for the start and the end of a turn than RSKI is.
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