INTRODUCTION: Ski boots may offer the potential to substantially alter joint loading in skiing. While generally softer boots did not find great acceptance in the skiing community a specific change in ankle flexion-extension range has been suggested as a possible pathway (Schaff & Olbert, 1996). However, no comprehensive investigations were published demonstrating the effect of such boots on skiing technique and joint loading. The purpose of this study was to test the effect of a modified ski boot on lower extremity kinematics and specifically the loading of the ankle joint complex during mogul skiing. METHOD: Nine male mogul skiers (20.9 ± 6.92 y) of the German national freestyle team participated in the study. A custom-built mobile 6 DoF force measurement device and a high speed camera system (Simi Motion) were used for data collection in the field. The collected data were used as input to a 30 full body musculoskeletal model (Anybody Technology & Fig. 1) to calculate lower extremity joint kinematics as well as net joint moments, muscle and joint forces at the ankle joint. RESULTS: The ski boot modification allowed for a slightly greater range of movement at the knee and ankle joints and a more forward positioning of the centre of mass with respect to the ski. Joint moments, joint and muscle forces at the instant of maximum reaction force when approaching a mogul were significantly reduced (Fig. 2). Perception questionnaires demonstrated that the shoe modification was well accepted. DISCUSSION: This specific boot modification significantly reduced ankle joint loading while all skiers reported a positive effect on their control in this particular situation. No other study has yet demonstrated such a change. It needs to be assessed what for example the requirement for changes in other equipment components may be using such boots. CONCLUSION: Boot modification allows for a reduction of ankle joint load. If this applies for the knee joint needs to be confirmed. This line of research may offer new insights and will allow to assess effects of equipment developments in skiing. ACKNOWLEDGEMENTS: We greatly appreciate the contributions of Peter Spitzenpfeil and Veit Senner, TU Munich, as well as the help of the AnyBody Research Group, Aalborg University.
© Copyright 2012 Science and Skiing V. 5th International Congress on Science and Skiing, Dec. 14 - 19, 2010, St. Christoph am Arlberg. Veröffentlicht von Meyer & Meyer Sport (UK) Ltd.. Alle Rechte vorbehalten.