180921 How do you measure the performance of an alpine athlete to get more gold medals? Check out our on-going field work in Switzerland!
How do we get more medals?
Pictures from Saas Fee and our field tests at Ski Team Swedens training camp, professor Matej Supej on the slope assisted by Alessandro and Mads. Scroll down and our performance engineer Alessandro will explain to you what we are doing.
From the 20th to the 25th of September, our team will be performing measurements on the Swiss slopes of Saas Fee. Our goal is to provide the skiers of the Swedish alpine team a tool to analyse and evaluate their performance during trainings – this can make them better (read; more medals!).
Are you a skier yourself? Have you ever wondered how to measure a skier’s technique? Our team uses different technological solutions (GNSS, IMUs and pressure insoles) to provide information about a skier’s kinematics and dynamics.
The GNSS (Global Navigation Satellite System), which is very similar to your smartphone’s GPS, makes use of an antenna, which receives radio signals from satellites orbiting around the Earth. The antenna, that we chose to place on the skier’s back protector, uses these signals to estimate the position and speed of the skier. Data are then sent via Bluetooth to a tablet and stored in it’s memory. Our system, unlike the most common GPS devices, is very particular: it allows us to get very accurate data (within 1-2 centimeter accuracy) at a high rate (a measurement is taken every 50 milliseconds)! These features are essential for us: in alpine skiing, movements are extremely fast and even small differences make a big difference in high-level competitions.
IMUs (inertial measurement units) consist of accelerometers and gyroscopes that measure, respectively accelerations and angular velocities. Some words can be complicated if you are not used to them but these data allow us to calculate the sensor’s orientation and position in the space. When an IMU is attached to a body segment, the orientation and position of the segment itself is estimated. The Xsens suit that we are using consists of 17 IMUs (one for each body segment considered in the model) attached to a Lycra suit and allows to build a full-body biomechanical model of the skier, providing information about their technique.
Finally, pressure insoles look like normal insoles, but contain a flexible and thin sensor that measures the force between the foot and the ski boot. An estimation of forces acting on the forefoot and the heel are provided separately, allowing to get information about the skier’s posture. Moreover, asymmetries can be detected if the skier tends to put more weight on one side compared to the other. An app allows to see data in real-time and store them.
The final step for our team is to analyse the collected data and present them in such a way that athletes can make the best out of them and improve their performance in competition!