Skilog: A Smart Sensor System for Performance Analysis and Biofeedback in Ski Jumping
Lukas Schulthess, Thorir Mar Ingolfsson, Marc Nölke, Michele Magno, Luca Benini, Christoph Leitner
October 2023
Abstract
Skilog is a wearable system designed to assist ski jumpers by analyzing take-off mechanics and providing real-time biofeedback. Pressure-sensitive insoles in each boot sample at 100 Hz and stream to an embedded GAP9 microcontroller, where an XGBoost model classifies the athlete’s jump phases. The system achieves 92.7% accuracy in classifying jumps and offers immediate feedback on timing and technique while weighing about 20 g and consuming little power, enabling multi-day operation.
Key Highlights
- Pressure-sensitive insoles feeding an XGBoost classifier deliver 92.7% jump-phase accuracy for ski jumping.
- Runs entirely on a GAP9 MCU with low power consumption, enabling multi-day operation from a lightweight hardware setup.
- Provides immediate biofeedback to athletes and coaches to refine take-off timing and technique.

Postdoctoral Researcher
Making AI run on microwatts: I build foundation models for EEG, ECG, and other biosignals, and compress them until they run in real time on wearable devices, not in the cloud.