INTRODUCTION: Snowboardcross and ski cross are now official Olympic events, so physical preparation of these athletes has become a focus in sport science. At least four racers start together so the start is crucial. Video analysis has shown that in many cases the two fastest Starters advance to the next round of competition. In short track speed skating, results are influenced both by ability and start position and these factors are even more important in the semifinals and finals where skill levels are more homogeneous (Maw et al., 2006). The goal of this project was to develop a start tool to optimize the start performance of world class athletes. METHOD: The apparatus is an aluminium alloy (ITEM) construction. A snowboard or skis are mounted on a sled which glides with minimal resistance along a 6m long rail. Two U2B force transducers (HBM) are connected to the start handles to allow force measurements on both sides. A motion transducer (EMIX 3) on the sled and a magnetic band (MB20.20) on the rail enable displacement measurements. All data can be analysed and displayed by a LabView program (National Instruments Corp.). RESULTS: Members of the Austrian national snowboard and skiers cross teams were tested and also used the machine in training as a feedback tool. Dynamic parameters are collected out of the force-time curve (e.g. strength Impulse, maximum strength of the compression and the pull/push off phase, compression-pull/push off-ratio, position of the strength maximum, right-left-ratio). Kinematic parameters of the sled out of the velocity-time curve are maximum velocity of the pull/push off phase, temporal position of the velocity maximum, and velocity at the end of the push off when the hands leave the start handles. Another parameter is reaction time after opening of the start gate. Necessary measurements of reliability (Test-Retest) and validity (comparisons with on snow start measurements) with experienced racers (e.g. Skigymnasium Stams, ÖSV) accomplished scientific criteria. DISCUSSION & CONCLUSION: The positive effect of strength training depends on the accornpanying technique training to guarantee the necessary transfer. It has been shown that competitive performance, even in athletes with many years of experience, can be improved with parallel training of sport specific technique and general conditioning (Hakkinen & Komi, 1985). Consequently, the focus should be on developing sport specific testing and training tools. Machines developed for elite sport which are not commercially available must produce results that are highly objective, reliable and valid.
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