INTRODUCTION: Ski disciplines are several and each requires different gear and technique. Ground Reaction Force (GRF) during skiing has always been a key parameter to set requirements for gear aiming to improve performance and safety 1-3. The study presents a lightweight system to measure skiing GRF and relative angles between components of the boot during touring and alpine skiing. METHODS: Two commercial six-axis loadcells were positioned between the ski and bindings of a ski using adapter aluminum plates, adding to the original ski/binding assembly 0.5 kg mass and 20 mm height. GRF were obtained resolving the two load cells forces and moments at the center of the ski. Relative angles of the boot (shell/ski, shell/cuff, shell/tibia) were measured using a set of custom rotary potentiometers and electrogoniometers. The system was assembled to the right side of a pair of touring skis and alpine skis and preliminary field tests were conducted by a ski instructor both on fresh and groomed snow, after an indoor validation with 3D motion capture on force platforms. RESULTS: Validation of the system showed error within 4% for the vertical force, and 10% pitch/roll moments. Angles measured proved accurate at least as 5%. Field tests showed vertical loads up to 1800 N, roll moments up to 57 Nm and pitch moments up to 60Nm during a touring downhill turn. DISCUSSION/CONCLUSION: Paired with indoor validation, the system proved to be viable for field acquisitions. Original data were collected in uphill touring: downhill data agree with previous findings 2,3. Future development will address the improvements of load/angle components accuracy. The system is being used to test several skiers and gear to compare athletes` technique and gear tuning for performance and safety.
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