Author(s): BON, I., OCIC, M., RUŽIC, L., CIGROVSKI, V., Institution: UNIVERSITY OF ZAGREB FACULTY OF KINESIOLOGY, Country: CROATIA, Abstract-ID: 2557

INTRODUCTION:
Ski treadmill simulators are increasingly used for controlled biomechanical investigations and technique training in alpine skiing, yet their ecological validity relative to on-snow skiing remains insufficiently quantified. The aim of this study was to compare lower-limb joint kinematics during snowplough turns performed on a ski treadmill simulator and on an alpine slope, with emphasis on the central part of the turn when the outer ski is aligned with the fall line.
METHODS:
Four recreational skiers performed multiple left and right snowplough turns in both conditions. Three-dimensional kinematics were recorded using an Xsens inertial motion capture system. Each turn was temporally normalised and divided into three sections. The analysis focused on the middle section of the turn. The following joint angles were analysed: right knee flexion, right hip flexion, right hip abduction, left knee flexion, left hip flexion and left hip abduction. For each participant, mean values across turns were calculated for both conditions and compared within subjects. Multivariate differences between conditions were assessed using Hotelling’s T² test.
RESULTS:
Across participants and turn directions, the simulator condition showed consistently smaller joint motion amplitudes than during on-snow skiing. Knee flexion angles were reduced, and both hip flexion and hip abduction were systematically lower on the treadmill. A significant multivariate difference in lower-limb kinematics was observed between environments (p = 0.02). Despite preservation of the overall coordination pattern characteristic of the snowplough turn, the magnitude of joint motion was attenuated on the moving belt. These differences are biomechanically consistent with reduced turn closure and lower edge angle development on the treadmill, where constant belt motion and constrained lateral displacement limit the skier’s ability to complete the turn and generate larger external ski loading. Consequently, skiers adopted a more upright posture with reduced flexion–abduction coupling during the central part of the turn.
CONCLUSION:
The results indicate that ski treadmill simulators reproduce the fundamental inter-limb coordination of the snowplough turn but with reduced lower-limb kinematic amplitudes compared with on-snow skiing. Such environment-specific constraints should be considered when interpreting simulator-based biomechanical data and when using treadmills for technique acquisition and motor control research in alpine skiing.