Mont-Blanc 42K

Race strategy

Hold a steady pace and save energy for every section.

• Steep 29% wall. Control your pace and stay focused.
• 909m descent. Go easy, save your quads.
• Final 911m descent. Save your legs to go all out on it.
• Control your HR on the first climb, save your quads on the descents until 23.2km, then run your race pace, and start the final descent from 35.9km under control, then go all out near the bottom.
• Start · 0.0km–1.9km · Race-day nerves push your heart rate up: don't follow the crowd, find your own rhythm.
• Settle in · 1.9km–17.2km · Climb of 942m, high point 2172m. Plus 1 more climb. Ease in: hold back more than feels necessary. The race is still ahead. Climb by heart rate or breathing, not pace. Running pays off here: run wherever you can. Hike the steepest pitches.
• Work · 17.2km–29.7km · Descent of 909m averaging 15%, climb of 554m. 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.
• Fade · 29.7km–35.9km · Plus 1 more climb and 1 descent. Your energy fades, and that's normal: hold a steady effort and stop counting the miles. Climb by heart rate or breathing, not pace. Your heart rate drifts down on its own: don't chase your early-race numbers, go by feel.
• Home · 35.9km–43.0km · Descent of 911m averaging 13%. 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

The course climbs 2540m+. With 60m/km of climbing, this is a true mountain course with sustained climbs and descents. By gradient, 43% of the distance is uphill, 41% downhill and 16% flat. The longest climb runs 6.8km at an average 13.8% grade (942m of vertical). The longest descent runs 7.0km at an average 13.0% grade (911m of vertical). The steepest climb averages 29.2% over 0.8km. The steepest descent drops at 32.8% over 0.3km. Surface: 84% trail, 10% road, and 6% smooth. Flat-equivalent effort: 63.9 FlatKM.

Summits

The highest summit on the course is Aiguillette des Posettes (2201m), 17.1km from the start. Other named summits along the route: Le Béchar (1720m).

Poles

Poles bring little benefit here: only about 9.0km of pole-friendly terrain.

Quad damage

Quad damage risk is moderate (index 33 of 100), with 45% of the load in the first half: 1 descent deserves a plan and a couple of downhill sessions before race day.

• Control your HR on the first climb, save your quads on the descents until 23.2km, then run your race pace, and start the final descent from 35.9km under control, then go all out near the bottom.
• #1 · 17.2–23.2 km · 909 m D−, -15.1% · 19.8 km ahead → control
• 35.9–42.9 km · 911 m D−, -13.0% · 0.0 km ahead → even, first half under control, let go at the end

Weather

On race day, start temperatures have historically ranged from 9°C to 18°C, with around 13°C at the highest point; the chance of precipitation is about 49%. Heavy rain of 10.0mm or more falls on about 8% of days around this date.

Results

1,999 finishers completed the 2026 edition. Men's winner: Rémi BONNET (Switzerland) in 3:33:14. Women's winner: Tove ALEXANDERSSON (Sweden) in 3:55:07.