When Sabastian Sawe crossed the line at the TCS London Marathon on April 26, 2026, in 1:59:30, the headlines wrote themselves: the first official sub-two-hour marathon, the long-promised barrier finally falling in legal race conditions. But buried in almost every recap was a second, quieter story — the shoes on his feet. Sawe ran the record in a pair of Adidas Adizero Adios Pro Evo 3s, a 97-gram slipper of foam and carbon that didn't exist five years ago and would have been illegal under the rules in place a year before that. His training was extraordinary. So was his footwear.
For the full breakdown of the race — the splits, the negative split that finally cracked the barrier, the all-time list reshuffle — read our deep dive on how Sabastian Sawe broke the 2-hour marathon. This piece is about the other half of the equation: the technology that made it possible, and what it means for everyone else lacing up on race day.
What "super shoes" actually are
The term gets thrown around loosely, but a super shoe is a specific recipe. Two ingredients matter: a thick midsole made of a new generation of foam (almost always PEBA — polyether block amide — sold under brand names like Pebax), and a stiff curved plate, usually carbon fibre, embedded inside that foam.
The foam does the storage. PEBA is unusually springy for its weight: independent testing has measured mechanical energy return of around 87%, compared with roughly 76% for the thermoplastic polyurethane (TPU) used in earlier "boost"-style foams and around 66% for the EVA that's been the running shoe default for decades. It's also 20–30% lighter than TPU at the same stack height, which is why super shoe midsoles can be tall without the shoes feeling clunky.
The plate does the leverage. By stiffening the forefoot, it stops the foot from collapsing through toe-off and turns the whole shoe-and-foot system into a longer, springier lever. Researchers debate exactly how much of the benefit comes from the plate itself versus the way it lets the foam do its job — but the consensus is that you need both. A plate without modern foam is dead weight. Modern foam without a plate compresses too easily.
The science: how big is the effect, really?
The "4%" number that gave the original Nike Vaporfly its name comes from a 2017 study by Wouter Hoogkamer, Shalaya Kipp and colleagues at the University of Colorado Boulder, published in Sports Medicine in early 2018. Eighteen runners — eight rearfoot strikers and ten mid- or forefoot strikers — were tested at three paces in three shoes: a Vaporfly prototype, a Nike Zoom Streak 6, and an Adidas Adios Boost 2. All eighteen ran with better economy in the Vaporfly. The mean improvement was about 4%.
That study was funded by Nike, which deserves to be flagged. But independent follow-ups have repeatedly landed in the same ballpark. A 2023 study at the University of Gloucestershire found a 3.9% reduction in oxygen consumption at recreational marathon pace, rising to 5.0% at faster paces. Reviews of the subsequent literature suggest most well-trained runners see somewhere between 2% and 6% economy improvement in modern PEBA-and-plate shoes versus traditional racing flats. Some individuals see almost nothing. A few see double digits.
The translation from "running economy" to "race time" isn't 1:1 — economy gains roughly map to two-thirds the percentage in time saved, because of how oxygen cost relates to pace. A 4% economy gain is closer to a 2–3% time improvement. For a 3:30 marathoner, that's four to six minutes. For a 4:30 marathoner, it's potentially seven to nine. For Sawe, a 3% margin on a 2:03 fitness level is roughly the difference between a normal world record attempt and 1:59:30.
A short timeline of how we got here
- 2017: Nike releases the Vaporfly 4%, the first commercially available shoe with a full-length carbon plate buried in PEBA foam (Nike's "ZoomX"). Eliud Kipchoge wears a prototype at the Breaking2 attempt in Monza, running 2:00:25.
- 2019: Nike refines the design into the Vaporfly Next%. On October 12, in a closed-course event in Vienna, Kipchoge runs 1:59:40 in a prototype Air Zoom Alphafly Next% — a chunkier sibling of the Vaporfly with two Zoom Air pods in the forefoot. Because of the rotating pacers and the bottle-on-a-bike, it doesn't count as a record, but the message lands: sub-2 is real.
- Early 2020: World Athletics, scrambling to keep the rules ahead of the technology, caps road shoe stack heights at 40mm and limits competition shoes to a single rigid plate. The retail Alphafly squeaks under the limit.
- 2023: Kelvin Kiptum runs 2:00:35 in Chicago, breaking the world record by 34 seconds in Nike Alphaflys.
- 2026: Sabastian Sawe runs 1:59:30 at London, the first sub-two-hour marathon ratified as a world record, in a pair of Adidas Adizero Adios Pro Evo 3s reportedly weighing 97 grams. Yomif Kejelcha runs 1:59:41 behind him in the same shoe. The era of carbon-and-foam dominance is, at this point, total: every men's top-ten time on the all-time list has been set in a super shoe.
The Vaporfly effect, then and now
Researchers sometimes call it the "Vaporfly effect" — the visible step-change in elite marathon times after 2017. World records in the men's marathon dropped by more than two minutes between 2014 and 2024. Women's records dropped by similar margins. Half-marathon and 10K times shifted too. Some of that is generational talent (Kipchoge, Kiptum, Kosgei, Chepngetich, now Sawe and Assefa); a meaningful portion is the shoes.
The interesting part is that the rate of improvement seems to be slowing. Between 2017 and 2020 the gains came fast as brands scrambled to copy Nike. Since the World Athletics rules locked in the 40mm cap and single-plate limit in 2020, progress has come from foam chemistry rather than ever-thicker stacks. The Adios Pro Evo 3 that Sawe wore is, by Adidas's own claim, only about 1.6% more economical than the Pro Evo 2 — a much smaller jump than the original Vaporfly delivered. We may be approaching a ceiling.
Are carbon plate shoes worth it for the rest of us?
This is the question every amateur asks and very few honest answers get given. Here's our attempt.
The economy gain is real for recreational runners — the 2023 Gloucestershire study confirmed it at 9:40-mile paces — but the absolute time savings shrink as you slow down. A 3% economy gain over a sub-2:30 marathoner adds up to several minutes; over a 5-hour marathoner it's perhaps two or three minutes, and the variance between individuals is large enough that some runners may see no benefit at all. Stride mechanics matter: the plate's leverage advantage is most pronounced at faster cadences and longer flight times. Slower runners with shorter strides extract less from it.
Then there are the trade-offs:
- Price. Most current super shoes retail between $250 and $500. The Adios Pro Evo 1, when it launched, was a one-race $500 shoe.
- Lifespan. PEBA foam degrades faster than EVA. Most racing super shoes are good for 150–250 miles before performance noticeably drops. One study measured a roughly 2.3% economy loss in heavily worn PEBA shoes versus fresh ones — almost half the original benefit gone.
- Injury risk. The combination of a tall stack and a stiff plate changes how forces travel through the foot and lower leg. There are no large epidemiological studies yet, but coaches and physios consistently report increased calf, Achilles and bone stress complaints in runners who jump straight into super shoes without adapting.
The reasonable approach for most amateurs: own one pair, use them for goal races and the occasional key workout, do the bulk of training in regular daily trainers, and introduce them gradually so the calves and Achilles get accustomed to the new mechanics.
The current 2026 racing field
The shoes elites are actually wearing right now is a more crowded picture than it was in 2019, when Nike was effectively unopposed. Currently competitive racing models include:
- Adidas Adizero Adios Pro Evo 3 — the 97-gram shoe Sawe and Kejelcha used to break two hours, and Tigist Assefa used to set a women's-only world record on the same day.
- Nike Alphafly 3 — the shoe Kelvin Kiptum wore for his 2:00:35, still the benchmark Alphafly generation.
- Asics Metaspeed Sky Tokyo and Edge Tokyo — the Sky for cadence-driven runners, the Edge for stride-extenders.
- Saucony Endorphin Elite — popular among American marathoners and 5K-to-half specialists.
- Puma Fast-R Nitro Elite 3 — the visible-plate, split-midsole design that several top finishers in London 2026 chose.
- New Balance SC Elite v5 — firmer and more aggressive than its rivals, with a 100% PEBA midsole.
- Hoka Cielo X1 3.0 — the most stable of the bunch, built for runners who find traditional super shoes tippy.
- On Cloudboom Strike LS — the shoe Hellen Obiri used to win Boston 2024.
Independent reviewers tend to rank performance differences between these in the low single digits. For most runners, fit and feel matter more than the brand on the heel.
Where the technology goes next
Two forces will shape the next few years. The first is regulatory. World Athletics has already shown willingness to legislate — the 40mm cap and the single-plate rule in 2020, and the updated Athletic Shoe Regulations that took effect on January 1, 2026 — and there's pressure from athletes and coaches to push the cap lower. A 35mm or 30mm limit would force a redesign of every current racing flat on the market.
The second is materials science. The easy gains from switching EVA to PEBA have largely been booked. New foam compounds — supercritical-foamed PEBA blends, hybrid PEBA/TPU systems, the next generation of Lightstrike Pro and ZoomX — are still delivering small improvements, but the curve is flattening. Whoever cracks the next foam formulation, or finds a legal way to add elastic energy without a second plate, will own the next world record cycle. Whether that record is 1:58 or 1:55 depends on how aggressively regulators decide to push back.
Bringing it back to your race
For Sawe and the elite field, super shoes are the difference between the world record and second place. For the rest of us, they're a useful tool with real costs and a non-trivial chance of being worth the money — especially if your goal race is on a flat course and you've put in the training to make every saved second count.
Curious how much faster a 3% economy gain would actually make you? The honest way to find out is to plug your current marathon time into the calculator at runpace.co and try shaving 2–3% off — that's the realistic time-translation of the running economy benefit super shoes deliver. And if you want the full story of the run that finally broke the barrier, our Sawe 5K-by-5K breakdown walks through every split.