Nike continues to rewrite the rules of trail running, pushing beyond the limits of research in both apparel and footwear. On one side there’s Radical AirFlow, the new breathable material that leverages the principles of fluid dynamics to turn air into an ally for athletes; on the other, the ACG Ultrafly, a super shoe forged over thousands of test miles, designed for those who choose to run in extreme environments.

Radical AirFlow, then, ushers in a new era in technical apparel, engineered to help the body speed up its natural cooling processes. No longer just mesh and vents: Nike has designed real air channels inside the fabric, able to capture and direct airflow toward the skin, amplifying sweat evaporation. This technology draws on athletes’ first-hand experience on the trails, tested in extreme conditions such as races in the Sierra Nevada, and will be crucial in a future where global temperatures continue to rise.

Alongside this revolution in apparel, Nike is also launching the ACG Ultrafly, a model that sets a new standard for trail running. After 13 testing cycles and more than 30,000 miles covered, the silhouette combines the lightness of ZoomX foam, the responsiveness of a carbon FlyPlate, and the grip of a Vibram Lightbase outsole. Every detail has been designed to ensure agility, stability, and comfort even on the toughest terrain, with a reworked upper that drains water and stays breathable.

If Radical AirFlow works to keep the body cool and light, the ACG Ultrafly powers every step with energy and control. Together they embody Nike’s vision for the future of trail running: an ecosystem where shoes and apparel are in dialogue, transforming mountain running into something even more natural and radical.

The ACG Ultrafly will therefore be available in spring 2026 on nike.com and at select retailers.