INTRODUCTION: The margin of technical skill differences between Austrian high performance junior ski racers is getting smaller and smaller. Precise analysis to allow even minor technique changes in this age group will lead to improved performance. Dynamic force measurements coupled with kinematics and electromyography analysis in ski racing have been made predominantly with adults. To our knowledge, no published work has analyzed the pressure distribution in Slalom (SL) with 11 to 14 year old high level junior ski racers. METHOD: Two girls and four boys (11 - 14 years) participated in the study. Performance levels of the skiers ranged from provincial to national and international performance. The SL with open gates was set on a medium steep slope. To simulate race conditions, the three runs were timed with an Alge Timing System. Ground reaction forces were analyzed with the Parotec System from Paromed. The skiers skied with an insole (24 hydro cells) in each ski boot and a data logger under the racing suit. The sampling rate was 200Hz. All runs were additionally recorded by three Video cameras (50Hz) and synchronized with the insole data. The sensors in the insole covered only 45 to 46% of the insole area (insoles 37d24 & 39d24) so estimated error was validated with a Kistler force platform, both statically and dynamically. RESULTS: When compared to the other skiers, the internationally successful youth skier (Fig 1.) had in most SL turns a continuous force-time curve with clear unloading. Outside to inside ski weight distribution was similar to a top ski racer with values from 50:50 to 70:30. Counter movement Jumps and static tests on a Kistler platform showed that approximately only 50 to 60% of real ground reaction forces were measured by the insoles within this kids. DISCUSSION and CONCLUSION: Powerful and efficient ankle movement synchronized with the total leg action together with stable hips and trunk are the most important differentiating factors in slalom technique. Ski boots in junior racers are often too stiff to make these essential ankle movements. The synchronization of Video and pressure distribution data made the technique analysis even in junior ski racing very effective. Statements about absolute values are difficult, but relative strength curves and ratios are sufficient (Spitzenpfeil et al., 2004).
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