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JOURNAL
OF
SPORTS SCIENCE &
MEDICINE
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Research
article
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A COMPARISON OF GROUND REACTION FORCES DETERMINED BY PORTABLE FORCE-PLATE AND PRESSURE-INSOLE SYSTEMS IN ALPINE SKIING |
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Kosuke Nakazato1,2  ,
Peter Scheiber1,2 and Erich Müller1,2 |
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1Department of Sport Science and Kinesiology, University of Salzburg, Salzburg, Austria 2Christian Doppler Laboratory 'Biomechanics in Skiing', Salzburg, Austria |
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© Journal of Sports Science and Medicine (2011) 10, 754 - 762 |
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| ABSTRACT | |||
| For the determination of ground reaction forces in alpine skiing,
pressure insole (PI) systems and portable force plate (FP) systems are well
known and widely used in previous studies. The purposes of this study were
1) to provide reference data for the vertical component of the ground reaction
forces (vGRF) during alpine skiing measured by the PI and FP systems, and
2) to analyze whether the differences in the vGRF measured by the PI and
the FP depend on a skier's level, skiing mode and pitch. Ten expert and
ten intermediate level skiers performed 10 double turns with the skiing
technique "Carving in Short Radii" as High Dynamic Skiing mode
and "Parallel Ski Steering in Long Radii" as Low Dynamic Skiing
mode on both the steep (23 °) and the flat (15 °) slope twice. All subjects
skied with both the PI and the FP system simultaneously. During the outside
phase, the mean vGRF and the maximum vGRF determined by the FP are greater
than the PI (p < 0.01). Additionally during the inside phase, the mean
vGRF determined by the FP were greater than the PI (p < 0.01). During
the edge changing phases, the mean vGRF determined by the FP were greater
than the PI (p < 0.01). However, the minimum vGRF during the edge changing
phases determined by the FP were smaller than the PI (p < 0.01) in the
High-Steep skiing modes of Experts and Intermediates (p < 0.001). We
have found that generally, the PI system underestimates the total vGRF compared
to the FP system. However, this difference depends not only the phase in
the turn (inside, outside, edge changing), but also is affected by the skier's
level, the skiing mode performed and pitch. Key words: kinetic analysis, alpine skiing, accuracy, skiing mode, pressure insole. |
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