Ever since Nike introduced the Vaporfly 4% in 2017, brands have competed fiercly to craft the ultimate road racing shoe. Commonly referred to as supershoes, this innovative footwear employs high-rebound foams and curved, rigid plates to enhance running efficiency while minimizing muscle damage.

　　Simply put, these high-performance shoes are engineered to make you run faster with greater ease. And they work, as proven in labs and on roads around the world. Designers have struggled, however, to harness the performance-enhancing benefits of road-running supershoes for the trail.

　　The Challenge of Trail Super Shoes

　　The difficulty stems from the very components that make a super shoe super: a stiff plate, combined with a tall stack of soft and bouncy midsole, creates an unstable and potentially ankle-breaking platform on the undulating and rocky terrain of trail running. To deal with the unpredictability of trails, companies have adjusted the full-length stiff plates found in road supershoes and introduced forked- or parallel-plate designs, aiming for enhanced flexibility and adaptability to diverse terrains. While they’ve succeeded in creating comfortable and capable trail supershoes, some award-winning and podium-gracing, none have captured the full magic. Some shoes struggle to handle varied terrain effectively while others fail to deliver the efficiency and recovery benefits witnessed in road supershoes.

　　As one of Outsides shoe testers for the last nine years, I can confidently say that no plated trail supershoe to date has delivered the same level of ride and benefits as provided by road-running counterparts. Until now.

　　Adidas Terrex Agravic Speed Ultra Weight: 9.5 oz (men), 8.1 oz (women)

　　Stack Height: 38–30 mm

　　Drop: 8 mm

　　Sizing: 6-13, 14 (men’s), 5-11 (women’s)

　　Pros and Cons

　　⊕ Fast, smooth, and lively ride

　　⊕ Adaptive stability

　　⊗ Not great in really rocky terrain

　　$220 at Huckberry (Mens) $220 at Running Warehouse (Womens)

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　　Adidas Terrex Agravic Speed Ultra Review

　　The Terrex Agravic Speed Ultra is the culmination of a two-year collaborative project with adidas professional runner Tom Evans, driven by the singular goal of creating footwear optimized for speed in the Western States Endurance Run, which Evans won in 2023, and Ruth Croft won in 2022, both wearing a prototype. The strategy was to leverage the successful elements found in their road supershoe, the Adizero Adios Pro 3, and tailor them specifically for trail running.

　　Having tested both the Adizero Adios Pro 3 and the Agravic Speed Ultra, I can vouch that the adidas team was successful. During my testing, the Agravic Speed Ultra exhibited a lively, forward-propelling motion similar to that of the Adizero Adios Pro 3, with perhaps even a little more bounce.

　　The Agravic Speed Ultra features an ultralight, hyper-bouncy, gas-infused TPEE Lightstrike Pro midsole with embedded, curved Energy Rods (like the Adizero Adios Pro 3). In lieu of a solid plate, Adidas uses independent rods that roughly parallel the bones in the foot, and are made of Pebax in its hard plastic form as often found in track spike plates. The Agravic Speed Ultra’s trail-specific configuration features four prongs in the forefoot and two in the heel, which are splayed wider and closer to the edges than those in Adidas’s road shoes to enhance stability, and flex independently, to adapt to uneven terrain underfoot.

　　Deep, sculpted sidewalls surround the heel, delivering secure landings, and a narrow midfoot waist widens to a generous, flared forefoot, providing an agile and stable stance. The aggressively rockered shape from heel to toe feels pronounced and a bit odd out of the box but comes to life on the run. The shoe naturally lands midfoot first, but as your balance shifts forward, the rockered forefoot transitions your weight through the toes, giving the shoe an effortless forward roll. At nearly every pace, the shoe provided a propulsive thrust forward with each stride as my foot landed, compressed the foam in the scooped curve of the rocker—that starts at just the right location past the ball of the foot—and rebounded as I rolled onto my toes.

　　One of the biggest concerns with any plated trail running shoe is the potential for the stiff plate to induce lateral instability, torquing or bouncing the stride sideways when it becomes unbalanced. My typical local testing loop is a winding, hilly, smooth singletrack with significant off-camber footing and short sections of modestly rocky and technical footing. For such a tall shoe (38mm/30mm), I was worried all the off-camber running would be dicey; however, I found the Agravic Speed Ultra to fare considerably well. Between the spacing and flexibility of the Energy Rods and the wide forefoot, the shoe felt controlled through all terrain challenges. I did feel that the stack height started to feel tippy in extremely rocky terrain, and for truly technical trails, I would want a shoe that sits closer to the ground.

　　One of Cory Smiths routes for testing the Adidas Terrex Agravic Speed Ultra:

　　I usually approach running downhill cautiously, consistently keeping one foot on the brake, but when wearing the Agravic Speed Ultra’s, I experienced a bit of a personality change. The combination of the rockered heel, cushioned midsole, and grippy outsole instilled confidence, enabling me to cast aside my typical timidity and unleash a more unrestrained approach downhill. In other words, I bombed down slopes with abandon.

　　The Agravic Speed Ultra absolutely shines on smoother, runnable terrain where you can put the pedal to the metal without hesitation. My pace quickened in smooth, open terrain without much additional effort. The shoe naturally wants to move fast and efficiently. The faster and harder you push it, the more energy it gives back.

　　The foot-hugging, breathable upper is made with thin woven abrasion-resistant mesh. Strategically placed overlays add durability and support. As is common for a racing shoe, the tongue, heel collar, and counter are razor-thin with no extra padding or support to keep weight to a minimum. While I found the midfoot lockdown to be on point, the thin, unstructured heel allowed some heel lift. This wasn’t enough to cause performance issues, but a more supportive heel would be nice on the trail.

　　The Agravic Speed Ultra features a thin version of Adidas’ signature grippy Continental rubber outsole. To enhance traction during cornering, the outsole employs 2.5mm lugs inspired by bike tire design, with slightly larger 3mm lugs on the edges for an increased bite when cornering. I found the grip on packed dirt and rock to be outstanding; however, the rather shallow lug depth felt skittish on loose kitty-litter-type footing.

　　While we haven’t yet tested the performance gains in the lab, my experience in the adidas Agravic Speed Ultra—and that of other Outside testers, some who reported running four to five percent faster than usual with the same effort—convinces me that it compares with carbon-plated road marathon racers and stands out as the first plated trail shoe that earns the title of supershoe. And it delivers these benefits without compromising its trail-handling creds. It impressed us enough to garner our Editors’ Choice award for best new running shoe this year.