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Innovation at the service of athletes: EPFL develops magnetic gates to track ski racers’ performance

A research team from the École Polytechnique Fédérale de Lausanne (EPFL) recently developed a new system which allows to measure a slalom skier’s exact time at each gate all the way down the slope. It also calculates the skiers’ speed and trajectory more accurately than GPS. Such precise measurements are crucial to analyse and improve athletes’ performance.

Whether they are racing slalom or giant slalom, ski racers all aim to go around the gates as fast as possible. But when it comes to carefully analysing their performance, existing technologies provide only limited information. This includes some split times along with video images – which have to be reviewed manually. Coaches have also tried GPS-based systems, which track the skiers’ speed and trajectory, but they are not always user-friendly.

Benedikt Fasel and the team at the EPFL’s Laboratory of Movement Analysis and Measurement (LMAM) have now come up with a way to closely track performance on each section of the slalom course by drawing on several different technologies. Fasel explains: “We found that by combining systems designed for different purposes, we could determine a skier’s time, speed and trajectory both accurately and automatically.”

In particular, the researchers added a magnetic system to measure the elapsed time at each gate. They equipped every gate with a magnet and put a magnetometer on the skier. “The magnetic field is strongest when the skier rounds the gate”, says Fasel. He adds: “If we know the amplitude, we can also calculate the distance. Using this information, we can figure out how far the skier is from the gate and determine the speed.” Since the exact position of the gates is known, errors in the acceleration-based speed and trajectory calculations can be corrected at every gate. In close collaboration with the Swiss Ski Federation “Swiss-Ski”, the researchers’ method was successfully tested on the slopes and the EPFL lab has filed a patent for this innovative technology.

Benedikt Fasel concludes: “Our ultimate goal is to help athletes and coaches identify room for improvement on the basis of scientific data rather than intuition. The magnets let us map the skier's trajectory with precision. So we can analyse the line the skier takes and their strengths and weaknesses.”

Magnetic gates track slalom skiers' performance

The Laboratory of Movement Analysis and Measurement (LMAM) is one of more than 350 EPFL-based labs and is highly specialised in using biomechanical instrumentation for measuring and modelling human biodynamics in daily conditions, during spontaneous activity or physical exercises. The lab’s newest innovation is yet another example of the academic excellence flourishing in the region and available to sport organisations and businesses.

Read here the full EPFL release.