UTDS 100KM

UTDS 100KM
The perfect balance between speed and endurance

Starting from Sart-lez-Spa, this 100 km section of the Ultra Trail des Sources immediately reveals its true character: 2,900 metres of elevation gain, challenging terrain and an intensity that leaves no room for half-measures. You’ll soon find yourself in the thick of the action, with a succession of irregular climbs, technical descents and constant bursts of pace that force you to find the right rhythm from the very first kilometres.

The route takes you through the vast Ardennes forests, the deep valleys and the more open areas near the High Fens, where the terrain remains lively, often damp and sometimes unstable. Here, you cannot let yourself be guided by the profile: even the flat sections demand effort, and fatigue creeps in gradually but steadily.

The 100 km is the turning point: long enough to force you into proper ultra-management – nutrition, mental clarity, pacing – but still dynamic enough to maintain a race mentality.

If you start too fast, the course will make you feel it quickly; if you manage it well, it will let you show your true level.

And as the finish approaches, it is not the distance that makes the difference, but your ability to stay focused, get back on track, and keep going. Here, you are running an ultra. A real one.