• Corpus ID: 131995067

FIS-RANKING AND CARVING TURN FORCE PRODUCTION PROFILE

@inproceedings{Kernen2010FISRANKINGAC,
  title={FIS-RANKING AND CARVING TURN FORCE PRODUCTION PROFILE},
  author={Tapio Ker{\"a}nen and Simo Ihalainen and Esa Hynynen and Tiina Salo},
  year={2010}
}

• T. Keränen, S. Ihalainen, +1 author Tiina Salo
• Published 2010
• Medicine

INTRODUCTION: In the slalom ski race, the skier loses velocity during the turns and increases it between them (Haugen et al 2007). Because the turn phases are longer than the gliding ones, proper carving turn technique plays a crucial role. The skier controls the trajectory of the skis with force production and on-edge ski angles, trying to avoid excess velocity decrease. The purpose of this study was to evaluate the differences between high and low ranked skiers’ force productions to the skies during the carved turn. METHOD: Nine alpine ski racers performed 2-4 runs on a symmetric steep slalom slope. Internal ski boot pressures were measured with Parotec insoles (Paromed-System®, Germany) operating at a frequency of 200 Hz. Based on the video recordings, 3–6 turns from each subject were selected for analysis. Calculation of perpendicular force production to the outer ski was based on the plantar pressure data. The skiers were divided into two groups according to their FIS-rankings. Group HIGH varied from 14.12 to 18.13 and group LOW from 36.91 to 60.77. RESULTS: In group HIGH, force production through frontal part of the outer foot to the ski was greater than in group LOW (table 1). In both groups, centre of pressure was at the front during the whole turn cycle; - in group HIGH more than in group LOW (figure 1). There was statistically significant difference between the groups in the time-normalized centre of pressure trajectories (figure 1). DISCUSSION: Both groups had same kind of centre of pressure fore-/backward movement, which is associated with ski’s bending. Mediolateral movement of centre of pressure trajectory was larger in group HIGH than in group LOW. This can be connected with their more active ski’s on-edge angle control compared to the lower ranked group. At the higher edging angle the ski penetrates deeper in the snow and minimizes lateral skidding (Heinrich et al 2010). CONCLUSION: The higher ranked group was able to produce more force through frontal part of the foot to the ski and their centre of pressure trajectory had larger mediolateral movement than the lower ranked group.