A MECHANICAL APPARATUS (SKIING MODEL) EXECUTING TURNS ON CARVER SKIS

Abstract

INTRODUCTION: The use of carver skis has for years been the topic of discussions and new concepts of optimal skiing technique, assuming that realizing curves (carving) should be possible only by canting the skis on their edges without the necessity of lateral sliding or turning skis. Investigations objectivizing the real effect of mechanical factors on the beginning (release) and trajectory of curves are generally interfered with by the ‘biological system’ of the subjects (skier). METHODS: A mechanical apparatus (called: skiing model; see Fig. 1) was constructed which is able to pitch from one side to the other, can ‘lean’ forward or backward (to alter the center of gravity relative to the skis), and can be varied in respect to the angle of canting the skis (to alter the effect of the edges). Thus, the skiing model enables us to isolate the influence of different factors on carving (side cut of the ski, canting, center of force and initial speed, etc.). An exploratory study was realized on a prepared slope in a ski hall. To collect cinematographic data, the runs of the skiing model using different carver skis under distinct conditions were filmed by 2 synchronized Hi8-video-cameras. The carver’s turn radius and instant of pitching were determined and compared. RESULTS: Exceeding a critical speed, the skiing model executes constant turns. The turn radius of the skiing model and the instant of pitching to the other side are influenced by each of the above-mentioned factors. The figure (on the left) shows the trajectory of two different carver skis (side cuts with turn radius of respectively 17m and 9m). CONCLUSIONS: Exclusively controlled by external forces in combination with the internal geometry of the skiing model, this mechanical apparatus is able to realize different turns. There is no need for muscular force and biological regulation for carving if the moving system provides the proper mechanical conditions. These results should influence the discussion about how to teach, learn and optimize skiing with carver skis.