Extreme Challenge

Race strategy

Hold a steady pace and save energy for every section.

• 503m descent. Go easy, save your quads.
• Steep 42% wall. Control your pace and stay focused.
• All downhill to the finish: go all out!
• 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 28.3km, then run your race pace, and go all out on the final descent from 39.9km.
• Start · 0.0km–1.5km · Race-day nerves push your heart rate up: don't follow the crowd, find your own rhythm.
• Settle in · 1.5km–9.2km · Climb of 1111m. 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 · 9.2km–23.4km · Descent of 503m averaging 15%, climb of 1534m. 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 · 23.4km–39.9km · Descent of 1220m averaging 25%, climb of 1557m, high point 1732m. 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. Hike the steepest pitches. Your heart rate drifts down on its own: don't chase your early-race numbers, go by feel.
• Home · 39.9km–43.7km · Descent of 358m 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

The course climbs 4480m+. With 99m/km of climbing, the course is exceptionally steep, with long hiking-grade sections. By gradient, 51% of the distance is uphill, 40% downhill and 9% flat. The longest climb runs 11.6km at an average 13.5% grade (1557m of vertical). The longest descent runs 4.9km at an average 24.8% grade (1220m of vertical). The steepest climb averages 46.0% over 0.2km. The steepest descent drops at 42.0% over 0.4km. Surface: 71% trail, 13% smooth, 6% technical, and 5% road. Flat-equivalent effort: 92.7 FlatKM.

Summits

The highest summit on the course is Sveti Jure (1762m), 38.8km from the start. Other named summits along the route: Veliki Troglav (1658m) and Sveti Ilija (1642m).

Poles

Trekking poles are strongly recommended: about 11.3km of the course is steep enough for them to pay off.

Quad damage

Quad damage risk is moderate (index 34 of 100), with 38% 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 28.3km, then run your race pace, and go all out on the final descent from 39.9km.
• #1 · 9.2–12.6 km · 503 m D−, -14.7% · 31.1 km ahead → control
• #2 · 23.4–28.3 km · 1220 m D−, -24.8% · 15.4 km ahead → control
• 39.9–43.7 km · 358 m D−, -9.4% · 0.0 km ahead → even, let go at the end

Weather

On race day, start temperatures have historically ranged from 16°C to 23°C, with around 7°C at the highest point; the chance of precipitation is about 30%. Heavy rain of 10.0mm or more falls on about 6% of days around this date.