Kinetic keys to alpine skiing performance: A 3-D analysis of ground reaction forces and torques

Alpine skiing performance hinges on the dynamic interaction between the skier and the ski-snow interface. Ground reaction forces are fundamental in controlling these interactions, yet surprisingly little research exists characterising 3-D turn kinetics. This study aimed to profile the evolution of ground reaction forces and torques signatures applied by skiers during turning and explore their link with giant slalom performance. Seventeen male alpine skiers with varying skill levels, equipped with ski-mounted force plates, executed multiple trials on a giant slalom ski course. A statistical parametric mapping approach was used to explore relationships between normal force and anteroposterior torque signatures with race times. Faster race times were correlated with greater normal force during the plateau phase of the turn crux (p < 0.001) and lower during turn switch (p = 0.006). Better times were also associated with higher positive (p = 0.004) and negative (p < 0.001) rates of force development. The best skiers appeared to apply an elevated positive M_y plateau (p < 0.001) with a steeper slope (p = 0.029) on the inside ski at turn initiation. Our findings indicate generating large forces and rapidly modulating their application to the skis is a crucial aspect of skiing performance.