adidas TERREX Innsbruck Alpine Trailrun Festival K42: Steep Uphills in Europe at the Marathon Distance (43.4km, 2,400m D+)

Extremely steep for a marathon-distance race. The K42 ranks 39th out of 390 European ultras for average uphill gradient steepness — only 38 races climb more steeply on average — and its D+/km of 55.3m/km ranks 85th out of 390 (top 22%), meaning every kilometer of the 43.4km delivers meaningful climbing. The combination of high D+/km and top-10% average gradient defines it as a dense climbing race despite not reaching ultra distance. Official D+: 2,400m.

The K42 starts at 07:00 from Mutters, a village southwest of Innsbruck, and follows a varied route through impressive mountain landscapes. Key highlights include steep climbs over the Mutterer Alm and into the Axamer Lizum ski area before ascending to the Nordkette — Innsbruck's iconic skyline mountain, visible from the city center. The course features technically challenging trail sections, flowing runnable passages between climbs, and breathtaking panoramic views. Official D+: 2,400m; D-: approximately 2,780m (per official race page), reflecting net descent from Mutters toward Innsbruck.

Yes — the K42 Trail Marathon is a UTMB Index 50K race and carries 2 ITRA points. Full ITRA race name: adidas TERREX Innsbruck Alpine Trailrun Festival K42 Trailmarathon. Mandatory equipment is required and includes a rain jacket rated minimum 10,000mm water column, first aid kit, mobile phone with SOS EU ALPS app installed, mountain rescue insurance, rescue blanket (210 x 160 cm), and a beverage container of minimum 1 liter (no cups provided at aid stations). A mandatory race briefing is required for all K15-K110 participants before the start.

Yes — all distances at the 2026 adidas TERREX Innsbruck Alpine Trailrun Festival sold out, including the K42. The 2026 edition ran April 29 – May 2, with the K42 on Saturday May 2 at 07:00. Registration for IATF27 (May 5-8, 2027) opens September 9, 2026 at 09:09 AM. Capacity for the K42: 1,611 places; entry ran €115 (2.65 €/km AUTO). Festival distances range from K7 Nighttrail (8.2km) to K110 Masters of Innsbruck (112.6km).

Innsbruck Airport (INN) is approximately 15 minutes from the city center — the most convenient arrival option. Munich Airport (MUC) is approximately 2–2.5 hours by road. Accommodation in Innsbruck is very easy to arrange with abundant hotel inventory across all price ranges. No car is needed: Innsbruck has excellent train and city transit connections, which is unusual for an alpine trail race. The K42 starts at 07:00 from Mutters; check innsbruckalpine.at for bib distribution schedule and mandatory race briefing logistics.