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Mont-Blanc Marathon
42km4223km2310km103.8km3.8

Mont-Blanc 90K

June 25
Chamonix,
France
utmb·source

Race Pace Calculator · GPX Analyzer · Trail Finder

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Read

  • How to Taper for a Marathon, Half Marathon or Ultra
  • Types of Runs and What Each Workout Actually Trains
  • Hill Training for Trail Runners: Train the Descents

Full calendar: France

Mont-Blanc 90K · Race profile

Max
2469m
Min
1035m

About Mont-Blanc 90K

Mont-Blanc 90K is the ultra trail at Mont-Blanc Marathon 2027 (Chamonix, France). The race starts on June 25, 2027.

Race strategy

Hold a steady pace and save energy for every section.

  • Big early climb with 1450m gain. Hold your pace, save your legs for later.
  • 697m descent. Go easy, save your quads.
  • Final 1347m descent. Save your legs to go all out on it.
  • 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 60.8km, then run your race pace, and start the final descent from 74.2km under control, then go all out near the bottom.
  • Start · 0.0km–1.7km · Race-day nerves push your heart rate up: don't follow the crowd, find your own rhythm.
  • Settle in · 1.7km–9.6km · Climb of 1447m, high point 2473m. Ease in: hold back more than feels necessary. The race is still ahead. Climb by heart rate or breathing, not pace.
  • Work · 9.6km–43.4km · Descent of 697m averaging 13%, descent of 841m averaging 13%, descent of 895m averaging 22%. 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. Hike the steepest pitches.
  • Fade · 43.4km–74.2km · Climb of 1188m, descent of 1133m averaging 11%, climb of 1111m. 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 · 74.2km–85.7km · Descent of 1347m averaging 12%. No heroics: settle back into your own effort and hold it to the line. Very long descent: first half under control, then even, let go only near the end. Hike the steepest pitches.

Course

By gradient, 49% of the distance is uphill, 43% downhill and 8% flat. The longest climb runs 9.6km at an average 15.0% grade (1447m of vertical). The longest descent runs 11.5km at an average 11.7% grade (1347m of vertical). The steepest climb averages 51.4% over 0.2km. The steepest descent drops at 46.9% over 0.3km. Surface: 87% trail and 6% road.

Summits

The highest summit on the course is L'Arolette (2330m), 50.5km from the start. Other named summits along the route: Tête de Balme (2321m) and Tête de Bellachat (2276m).

Poles

Trekking poles are strongly recommended: about 16.8km of the course is steep enough for them to pay off.

Quad damage

Quad damage risk is high (index 61 of 100), with 50% 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 60.8km, then run your race pace, and start the final descent from 74.2km under control, then go all out near the bottom.
  • #1 · 9.6–15.0 km · 697 m D−, -13.0% · 70.7 km ahead → control
  • #2 · 20.9–27.3 km · 841 m D−, -13.1% · 58.4 km ahead → control
  • #5 · 31.6–34.8 km · 544 m D−, -16.8% · 50.9 km ahead → control
  • #3 · 39.2–43.3 km · 895 m D−, -21.8% · 42.4 km ahead → control
  • #4 · 50.8–60.7 km · 1133 m D−, -11.4% · 25.0 km ahead → control
  • 74.2–85.7 km · 1347 m D−, -11.7% · 0.0 km ahead → even, first half under control, let go at the end

This page has a pacing and nutrition planner, a gradient matrix, an interactive elevation profile and historical weather for Mont-Blanc 90K.

Other distances of Mont-Blanc Marathon 2027Mont-Blanc 42K (42.0km)·Mont-Blanc 23K (23.0km)·Mont-Blanc 10K (10.0km)·Mont-Blanc KM Vertical (3.8km)

Other editions of Mont-Blanc 90K2026

Official websitewww.marathonmontblanc.fr/en