Jeju 100K

Race strategy

Hold a steady pace and save energy for every section.

• Big early climb with 1.7km gain. Hold your pace, save your legs for later.
• 1078m descent. Go easy, save your quads.
• 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 62.7km, then run your race pace.
• Start · 0.0km–1.3km · Race-day nerves push your heart rate up: don't follow the crowd, find your own rhythm.
• Settle in · 1.3km–22.3km · Climb of 1701m. Ease in: hold back more than feels necessary. The race is still ahead. Climb by heart rate or breathing, not pace. Hike the steepest pitches.
• Work · 22.3km–51.2km · Descent of 1078m averaging 10%, climb of 1408m, high point 1913m. 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. Hike the steepest pitches.
• Fade · 51.2km–101km · Descent of 1275m averaging 11%. Plus 2 more climbs 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. 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. Your heart rate drifts down on its own: don't chase your early-race numbers, go by feel.
• Home · 101km–110km · 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

By gradient, 36% of the distance is uphill, 38% downhill and 26% flat. The longest climb runs 22.3km at an average 7.6% grade (1701m of vertical). The longest descent runs 11.5km at an average 11.1% grade (1275m of vertical). The steepest climb averages 31.4% over 0.5km. The steepest descent drops at 30.6% over 0.9km. Surface: 53% trail, 28% road, 9% smooth, and 8% technical. Flat-equivalent effort: 139.3 FlatKM.

Poles

Poles bring little benefit here: only about 14.0km of pole-friendly terrain.

Quad damage

Quad damage risk is moderate (index 48 of 100), with 53% of the load in the first half: 2 descents deserve a plan and a couple of downhill sessions before race day.

• Control your HR on the first mountain, save your quads on the descents until 62.7km, then run your race pace.
• #1 · 22.3–32.6 km · 1078 m D−, -10.4% · 77.1 km ahead → control
• #2 · 51.2–62.7 km · 1275 m D−, -11.1% · 47.1 km ahead → control
• 91.9–101.5 km · 530 m D−, -5.5% · 8.3 km ahead → your pace

Weather

On race day, start temperatures have historically ranged from 20°C to 25°C, with around 11°C at the highest point; the chance of precipitation is about 32%.

Results

835 finishers completed the 2025 edition. Men's winner: Jianjian Yang (China) in 10:10:51. Women's winner: Leslie Nowicki (France) in 13:02:58.