Inthanon 50

Race strategy

Run easy on the first mountain, then go all out on the second.

• 662m descent. Go easy, save your quads.
• Start easy and control your HR up to 13.6km.
• Hold your race pace up to 25.5km, but stay in control.
• Control your HR on the first mountain, save your quads on the way down from it until 13.6km, then run your race pace, and go all out on the final descent from 34.0km.
• 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–13.6km · Descent of 662m averaging 6%. 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. This descent is hard on the legs: short steps, stay in control, poles if you have them.
• Work · 13.6km–25.5km · Climb of 889m, high point 1862m. Plus 1 more descent. This is where the race is built: steady, solid effort. Climb by heart rate or breathing, not pace.
• Fade · 25.5km–34.0km · Your energy fades, and that's normal: hold a steady effort and stop counting the miles. Running pays off here: run wherever you can. Your heart rate drifts down on its own: don't chase your early-race numbers, go by feel.
• Home · 34.0km–38.3km · Descent of 396m averaging 9%. No heroics: settle back into your own effort and hold it to the line. Long descent: keep it even and let go only near the end.

Course

By gradient, 38% of the distance is uphill, 46% downhill and 16% flat. The longest climb runs 7.9km at an average 11.2% grade (889m of vertical). The longest descent runs 10.6km at an average 6.3% grade (662m of vertical). The steepest climb averages 31.8% over 0.3km. The steepest descent drops at 33.7% over 0.3km. Surface: 56% trail, 30% road, and 13% smooth. Flat-equivalent effort: 58.1 FlatKM.

Poles

Poles bring little benefit here: only about 6.6km of pole-friendly terrain.

Quad damage

Quad damage risk is moderate (index 25 of 100), with 38% 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 mountain, save your quads on the way down from it until 13.6km, then run your race pace, and go all out on the final descent from 34.0km.
• #1 · 3.1–13.6 km · 662 m D−, -6.3% · 24.7 km ahead → control
• 21.5–25.5 km · 390 m D−, -10.0% · 12.9 km ahead → your pace
• 33.9–38.3 km · 396 m D−, -9.1% · 0.0 km ahead → even, let go at the end

Weather

On race day, start temperatures have historically ranged from 14°C to 20°C, with around 17°C at the highest point; the chance of precipitation is about 12%.

Results

832 finishers completed the 2025 edition. Men's winner: Miguel Arsenio (Portugal) in 3:27:59. Women's winner: Maude Mathys (Switzerland) in 3:54:26.