Merrell MTL ADAPT brings Kevlar and polymer science to ultrarunning

If you geek out over the nitty-gritty of trail shoe construction (and you regularly put your body through 50 to 100-mile races), you’ll want to meet the Merrell MTL ADAPT.

Developed inside the Merrell Test Lab (MTL) and shaped by feedback from elite ultra athletes, the ADAPT is designed to take on the gnarliest terrain over the longest distances, all without breaking stride.

With materials like Kevlar, dual-density polymer foam, and a Vibram Megagrip outsole, it resembles a Formula 1 car more than an everyday runner.

Merrell used MATRYX, the same material used in the Hoka Tecton X 3, a woven mesh made from ultra-tough polyamide fibres reinforced with Kevlar.

Yes, the same stuff used in bulletproof vests that adds durability without bulk, allowing the shoes to stay light and breathable while holding up to rocks, roots, and endless miles of abuse.

Inside that, there’s a layer of SBR rubber that helps wick away heat and keeps your feet cool during long races.

It's a small touch, but one that ultra runners will appreciate when they hit hour eight (or eighteen) on the trail.

Built to bounce back

Underfoot, you get FloatPro+, a clever midsole made from dual-density foam.

It's softer inside for cushioned landings, but tougher on the outside so the shoe doesn’t collapse after 50K.

Merrell says it uses a "multi-stage polymer fusion" process, science speak for a more durable, more consistent ride that stays responsive even deep into an ultra.

The heel-to-toe drop sits at 6mm, striking a balance between nimble and cushioned, and the midsole is said to be shaped to encourage natural transitions.

Grip-wise, the Vibram Megagrip sole is exactly what you’d expect on a top-tier trail shoe: sticky, confidence-inspiring rubber with 4mm lugs arranged to shed mud and bite into loose terrain.

But there’s another trick: the sole is geometrically segmented, meaning it flexes better around uneven ground and doesn’t feel like a slab of rubber stuck to your foot.

Throw in Merrell’s FlexConnect 2.0 channels – tiny cuts aligned with your foot’s natural movement – and you’ve got a shoe that adapts to terrain changes on the fly, especially helpful on technical descents or when the trail switches from dusty to damp in seconds.

The MTL ADAPT is available now at Merrell US, Merrell UK, and Merrell AU for the recommended retail price of $180/ £170/ AU$ 349.99.