TDS

Race strategy

Hold a steady pace and save energy for every section.

• 1391m descent. Go easy, save your quads.
• Big early climb with 1.9km gain. Hold your pace, save your legs for later.
• The finish is runnable. Save your legs to run it all the way.
• Long race. Control your HR and effort. Early mistakes cost the most.
• Control your HR on the first mountain, save your quads on the descents until 119km, then run your race pace.
• Start · 0.0km–1.4km · Race-day nerves push your heart rate up: don't follow the crowd, find your own rhythm.
• Settle in · 1.4km–12.0km · Climb of 1234m. Ease in: hold back more than feels necessary. The race is still ahead. Climb by heart rate or breathing, not pace.
• Work · 12.0km–67.2km · Descent of 452m averaging 16%, descent of 848m averaging 10%, high point 2585m, descent of 1391m averaging 12%. Plus 3 more climbs and 1 descent. This is where the race is built: steady, solid effort. Climb by heart rate or breathing, not pace. This descent is hard on the legs: short steps, stay in control, poles if you have them. Running pays off here: run wherever you can. At altitude your pace drops, and that's fine. Hike the steepest pitches.
• Fade · 67.2km–140km · Descent of 2268m averaging 9%, climb of 1325m, descent of 903m averaging 15%. Plus 2 more climbs and 2 descents. Your energy fades, and that's normal: hold a steady effort and stop counting the miles. Climb by heart rate or breathing, not pace. This descent is hard on the legs: short steps, stay in control, poles if you have them. Running pays off here: run wherever you can. Hike the steepest pitches. Your heart rate drifts down on its own: don't chase your early-race numbers, go by feel.
• Home · 140km–149km · 8.3km of runnable trail. No heroics: settle back into your own effort and hold it to the line. Running pays off here: run wherever you can.

Course

The course climbs 9100m+. With 59m/km of climbing, this is a true mountain course with sustained climbs and descents. By gradient, 40% of the distance is uphill, 40% downhill and 20% flat. The longest climb runs 12.8km at an average 15.0% grade (1916m of vertical). The longest descent runs 25.6km at an average 8.9% grade (2268m of vertical). The steepest climb averages 37.9% over 0.8km. The steepest descent drops at 46.6% over 0.5km. Surface: 64% trail, 18% road, 10% technical, and 6% smooth. Flat-equivalent effort: 238.6 FlatKM.

Summits

The highest summit on the course is Arête du Mont Favre (2442m), 11.9km from the start. Other named summits along the route: Tête du Lac de Roselette (2114m) and Bellevue (1801m).

Poles

Trekking poles are strongly recommended: about 26.2km of the course is steep enough for them to pay off.

Quad damage

Quad damage risk is high (index 75 of 100), with 46% of the load in the first half: 5 critical descents, the last of them run on already damaged legs. Downhill-specific preparation and a controlled early pace pay off here.

• Control your HR on the first mountain, save your quads on the descents until 119km, then run your race pace.
• #4 · 12.0–14.8 km · 452 m D−, -15.9% · 133.7 km ahead → control
• #3 · 20.2–28.8 km · 848 m D−, -9.8% · 119.7 km ahead → control
• #1 · 35.6–47.5 km · 1391 m D−, -11.7% · 101.0 km ahead → control
• #2 · 67.2–92.8 km · 2268 m D−, -8.9% · 55.7 km ahead → control
• #5 · 113.1–119.2 km · 903 m D−, -14.7% · 29.3 km ahead → control
• 136.0–140.2 km · 778 m D−, -18.4% · 8.3 km ahead → your pace
• Plus 1 more notable descent not listed: your pace.

Weather

On race day, start temperatures have historically ranged from 10°C to 20°C, with around 12°C at the highest point; the chance of precipitation is about 46%.

Results

1,207 finishers completed the 2025 edition. Men's winner: Antoine Charvolin (France) in 18:22:17. Women's winner: Careth Arnold (United States) in 22:58:52.