Preview : UTMB Istria

Istria 100 by UTMB: Open race on the men’s side, clearer hierarchy in the 50K

Andrzej Witek (UTMB Index 912)

The Istria 100 by UTMB weekend is shaping up to be a mix of wide-open racing and clear favorites, depending on which distance you look at.

On the 100-mile start line, there’s no dominant name — but there is structure.

Men’s 100M: One favorite, but no guarantees

Mark Darbyshire leads the field with a UTMB Index of 880, making him the strongest runner on paper. Still, the gap down to runners like Bartosz Gorczyca (855) is not decisive over 100 miles.

Behind them, a compact group including Juuso Simpanen and Johannes Low adds depth — the kind of field where mistakes matter more than raw ability.

Over this distance, the race is unlikely to be won early. It will come down to pacing, fueling, and who is still moving well after 12+ hours.

Men’s 50K: Different story entirely

The shorter race has a clear focal point.

Andrzej Witek (UTMB Index 912) stands out immediately — one of the highest-rated athletes racing anywhere this weekend.

With a gap of ~60 UTMB points to the next group, the race dynamic is simple:

• If Witek executes → he wins

• If not → the race opens instantly

Chasers like Sumng Kulung and Konstantinos Paradeisopoulos sit right behind, ready to capitalize.

Women’s 100K: Small field, clear top name

On the women’s side, the field is smaller but more defined.

Anna-Stiina Erkkilä leads with a UTMB Index of 760 and comes in as the most established name.

Behind her, runners like Monika Behro and Enrica Dematteis form a chasing group, but the gap suggests Erkkilä controls the race if she runs to her level.

What this weekend actually is

Istria isn’t a superstar-loaded UTMB race — and that’s what makes it interesting.

• The 100M → tactical, open, mistake-driven

• The 50K → top-heavy, performance-driven

• The women’s race → controlled, but still competitive