Super Shoes Revolutionized Road Running. Where Are They in Trail Running?

Greg Marshall
Aug 3
5 min read

close-up of trail running shoe as it kicks up some dirt

Super shoes have taken over elite road and tracking running in the decade since they first emerged with Nike’s invention of the Vaporfly 4%. After decades of running shoes that were sold on big promises for performance or injury-mitigation, the 4% stood out as the first one to hold up under scrutiny in a lab. When the team at the University of Colorado Boulder published their 2018 paper “A Comparison of the Energetic Cost of Running in Marathon Racing Shoes”, they foreshadowed what was to come– a generation of new world records on the road and the track, and a new paradigm in what the shoe on your foot could do for your own performance.

There’s a glaring omission there. One category of runner that hasn’t gotten the same boost that everyone else got when super shoes appeared: trail runners.

What is a super shoe?

Super shoes, or “advanced footwear technology” (abbreviated AFT), as they are usually called in scientific discussions, have three primary components that make them what they are. In no particular order, those features are:

A rockered geometry that helps roll you from your heel to your toe while your foot is on the ground
A “rigid moderator”, typically a plate of carbon fiber through the midsole of the shoe’s foam cushioning
Poly ether block amide (PEBA) foam, which is exceptionally light and springy, that composes the majority of midsole cushion

The properties of super shoes make a lot of sense for a runner who is traveling more or less in a constant forward direction on a flat, level surface. All three features of them allow the shoe to take up energy from the foot’s impact and to spring it back at toe-off.

The problem with trail is that runners are rarely traveling straight forward on a flat, level surface. Instead, they’re running up and down steep grades with lots of switchbacks, rocks, and roots. Does a shoe that stores your energy the way super shoes do, even make sense for the way trail runners move?

Research on trail running can be hard to do. Simulating rock and switchbacks on a treadmill in a laboratory poses some readily apparent challenges. Two recent studies provide some answers though.

Is AFT any good for trail runners?

A 2026 study led by Graham Askew at the University of Leeds had runners try running in super shoes on a treadmill at a few different grades of steepness to assess changes in oxygen consumption across the grades. If super shoes work as well for minimizing oxygen consumption on hills as they do on flat terrain, we’d expect to see between a 4 and 5% savings compared to a more standard running shoe.

Instead, what they found was that the benefit of super shoes decreases as the grade gets steeper. At a 3% grade, 4% savings had dropped to only about 2.5%. At a 9% uphill grade– still relatively tame by trail and mountain running standards– the benefit of the super shoe was down to fractions of a percent. More traditional EVA-based shoes worked just as well at 9-10% grades as the AFT shoe. That suggests trail runners might not find them worth the money, at least on the climbs.

But what about downhill running? The shoes could still be worth it on trails if they can save us some time on the descents. Another study out of the University of Canberra, led by Melissa Muzeau, examined what the shoes offer across three conditions: steep uphill (+10% grade), steep downhill (-10% grade), and on flat terrain (+0% grade). They didn’t use a full-fledged super shoe this time, instead focusing their comparison on the benefits of the PEBA foam, without the carbon plate. The previous study suggested that we shouldn’t expect much in the uphill condition, and we should already know what to expect in the flat condition too. Indeed, their results aligned with expectations in both of those categories. In the downhill condition though, super shoes offered little-to-no oxygen savings compared to a more traditional shoe either.

"Shoe manufacturer’s own internal research findings and development remain a mystery to the rest of us, but we know they’re doing it."

Muzeau's results make a lot of sense. If these shoes are springs giving us extra energy as we run along, that’s not necessarily a benefit when we’re descending a steep slope. As we put less energy into propelling ourselves forward and more energy into slowing ourselves down as we gracefully (or not) make our way down the hill, oxygen consumption will naturally drop anyway. In other words, a shoe that wants to spring us forward might not offer a lot when we’re using our energy to slow ourselves down.

So what does it mean for a footwear revolution in trail running?

For current super shoe designs, it doesn’t look good, but these were always designed with the road and track in mind. Still, there’s a few other details to consider.

For one, the same issue with representation shows up in these studies as in the majority of footwear research. Among the total 30 subjects involved in these two studies, all were male. It’s still not entirely clear how a female might respond differently to the same footwear technologies.

Second, there were a number of prototype shoes used by race leaders at this year’s Western States that we’re likely to learn more about over coming months. It’s possible that a modified geometry could hold some potential. Shoe manufacturer’s own internal research findings and development remain a mystery to the rest of us, but we know they’re doing it. The first author of the 4% study left a faculty position at the University of Massachusetts Amherst to head up applied research operations at Hoka at the beginning of the year.

Third, it’s worth remembering the nature of trail running. Races tend to be long– long enough that there’s reason to ask how much the metabolic savings from a super efficient shoe really means over, say, one hundred miles. Things that are likely to matter more in those scenarios are whether or not we experience heat, gut issues, blisters from ill-fitting shoes, or the unwanted effects of sleep deprivation. If all else were held equal, a couple of extra percentage points in oxygen savings still matter as elite ultra runners become more efficient in managing all of those other things.

It might not look the same as it does on the road or the track, but we haven’t heard the last of super shoes in trail running just yet.