When Ashley Mateo went through a recent track workout, something felt different. She hit her intervals faster than usual, her heart rate was lower, and her feet felt lighter. When she ran her next marathon, she achieved a personal record.
Ms. Mateo, a journalist and 15-time marathoner who reviews running shoes, believes she may have improved her performance thanks to the Adizero Adios Pro Evo 1 by Adidas, a new marathon race shoe with an eye-popping $500 price tag. There’s another catch: The Evo 1 lasts long enough for just one marathon, plus an unspecified “familiarization period.”
Despite her positive experience, Ms. Mateo isn’t sure the shoes are worth the cost, which she didn’t have to pay as a reviewer. “I don’t think the shoe is going to work for everyone,” she said.
The shoes are the lightest ever produced by Adidas and the latest entry in a heated competition to make the best carbon-fiber racing shoes. Only 521 pairs have been released to the public so far, targeted at runners who can run a marathon in 3 hours 30 minutes or faster.
Some runners who have raced in them say they can immediately feel a difference, and Tigst Assefa of Ethiopia ran the fastest marathon ever by a woman in a pair, shattering the previous record by more than two minutes at the Berlin Marathon in September.
Yet the shoes’ short shelf life has raised concerns and made some in the running community question whether the hype is deserved.
Aside from their lightness, the shoes’ other technology — a new foam and new structure — is unlikely to provide a big edge, if any, experts say. And at $500 per marathon and tryout run, they’re among the least sustainable shoes out there. Adidas said it intended to keep the price at $500, which, it added, “reflects the high-performance materials and designs within the product.”
“We have marketing claims and a pair of promises about improvements,” said Ross Tucker, an exercise physiologist who runs The Science of Sport, a popular blog for runners. “We have a world record in the marathon. But we don’t actually have any evidence, not compared to its peers and certainly not compared to its predecessors.”
Nike has long dominated the marathon racing shoe market with its Vaporfly line. A carbon-fiber plate in the Vaporfly’s midsole stores and releases energy with every stride. That, combined with a midsole foam called Pebax, catapults long-distance runners forward, improving times around 4 percent compared with average shoes.
Soon after its release in 2017 with its own hefty $250 sticker price, Vaporflys helped elite runners smash records. Other shoe companies followed suit, with New Balance, Saucony and Hoka among the brands to release carbon-plated shoes.
Adidas’s new shoe features three key developments. At 4.9 ounces in a men’s Size 9, it’s about 25 percent lighter than the latest Vaporfly. The company says the new foam boosts energy capture, and a change to the shoe’s design curves the sole up near the toes.
It’s well established in sports science that the lighter the shoe, the faster the runner. The weight difference between an Evo 1 and a Vaporfly might shave around 20 seconds off a marathoner’s time, said Geoff Burns, a physiologist at the University of Michigan who studies running biomechanics.
That’s the only improvement that would be likely to show up, Dr. Burns said, if he got down to testing the shoes in his lab. Changes in the foam and rocker are unlikely to be significant, adding at most “fractions of a percent in efficiency,” he said.
When the Vaporfly arrived, it took years of testing and a New York Times analysis to confirm the shoe’s speed boost, which turned out to be around 4 percent. The Evo 1, Dr. Burns said, isn’t much of a departure from the Vaporfly. It’s “the exact same recipe, with different spices added to the foam,” he said.
While researchers are skeptical of the Evo 1’s effectiveness, some runners have felt the benefits. Michael Ko, a runner who reviews shoes on his YouTube channel, “Kofuzi,” said the Evo 1, which he received from Adidas to review, felt fast, cushioned and light. He said he aimed to run his fastest half-marathon in them.
“They’re like nothing that’s out there,” Mr. Ko said. “You can tell there’s something special when you wear them.”
The shoe’s durability remains a worry. As with all race shoes, the trade-off for speed is less mass and support than standard running shoes. Racing shoes like the Vaporfly typically last at least four marathons, and Dr. Tucker and Dr. Burns expressed concerns that if the Evo 1 was good for only one marathon, it would show signs of degradation during the race itself.
“If you’re not a lightweight, pretty fast runner, who doesn’t absolutely destroy shoes, you’ll probably struggle to get even that out of it,” Dr. Tucker said.
That wasn’t the experience for Thomas Neuberger, a runner and the founder of Believe in the Run, a running news and shoe reviews site. Mr. Neuberger, who was sent a pair of the Evo 1s from Adidas, said the 2-ounce difference between the Evo 1s and Vaporfly had become stark at the end of a recent marathon.
“After a while, it’s kind of like holding a book above your head,” Mr. Neuberger said. “When you first hold that book, it doesn’t feel that heavy.”
The extreme payout for such a small improvement in performance is emblematic of the times in running, Dr. Burns said. Athletes exhaust every option at their disposal for the right price, whether it’s hiring a team of pacers to break a world record, jet-setting across the world or paying $500 for a pair of shoes you’ll wear just once, he said.
Ms. Mateo said that the rocker style of the shoe was her favorite part, and that the shoe “didn’t feel like it was at the end of its life” after the race. But she added that the cost, which she didn’t have to pay as a reviewer, was a nonstarter, and that feel was a matter of personal preference and biomechanics.
“They feel fast, but every runner responds differently to different shoes,” Ms. Mateo said.