Imagine walking into your local running store to buy a new pair of running shoes. After trying a few pairs, you settle on the one that feels the most comfortable: a thick-soled, highly cushioned shoe the shop employee endorses as their go-to shoe.
After months of training, you decide this is the shoe you’ll wear for your upcoming Boston Marathon qualifying race. Race day comes, and you nail a BQ! As you exit the finishing line corral, a course marshal pulls you aside and asks to see your shoes. After a quick look, the marshal notifies you that you are disqualified for wearing illegal shoes, and just like that, your BQ is no more.
While it may sound far-fetched to be disqualified for wearing illegal footwear, it’s technically within the rights of race directors who oversee U.S. Track & Field-certified courses to disqualify any runner that uses illegal footwear in competition—even if it isn’t actually common. That’s why it’s smart to understand banned running shoes. Here’s what you need to know before you lace up and head to the starting line.
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What are banned running shoes?
During the 2016 U.S. Olympic Marathon Trials, three Nike athletes (Amy Cragg, Shalane Flanagan, and Galen Rupp) wore prototype shoes with abnormally thick soles, and all three would go on to make podium finishes. Later that year, at the 2016 Rio Olympic Marathon, these prototype shoes impressed again, with the top three male runners (Eliud Kipchoge, Feyisa Lilesa, and Galen Rupp) wearing them.
These shoes would later become known as the Nike Vaporfly 4%, which officially launched in 2017. Designed with a curved carbon fiber plate sandwiched between a thick layer of Nike’s softest and highest rebound foam, ZoomX, the Vaporfly was thought to give runners better efficiency. Since its release, studies have also proven that it can, indeed, do so.
For the next three years, Nike athletes wearing the Vaporfly 4% set records, podium finishes, and fast times. Other brands struggled to produce a racing shoe that could match the Vaporfly 4%, giving Nike athletes an edge over their competitors.
To level the playing field among all shoe manufacturers, World Athletics, the international governing body for the sport of running, set standardized limitations on shoe design. The two most notable rules state that a runner cannot compete in any shoe with more than 40 millimeters of stack height (sole thickness) in the heel or more than one plate in the midsole. Coincidentally, Nike shoes were deemed legal under both of these standards.
Meanwhile, other brands continue to make shoes that technically fit into this banned running shoe category. As of the writing of this article, there are three banned running shoes on the market: the Adidas Prime X, New Balance Supercomp Trainer, and Asics Superblast. All three are banned from competition because they exceed the 40-millimeter stack height rule.
So does that mean you should ditch them, even if they feel so good and help you hit high speed? Maybe, but maybe not.
Are there benefits of banned running shoes?
Andrew Lemoncello, manager of running footwear at Adidas explains the most significant benefit of wearing banned running shoes is the recovery they offer your legs. “Not only do they help them recover after a race, but even during it, while you’re wearing them. That’s why they’ve been so successful,” he says.
This is because today’s midsole foams are lighter and provide more energy return than foams of six years ago. This allows brands to put more cushioning into a shoe, which can save your legs from the repeated bouts of hard concrete pounding they take when running.
In addition to the fast times Nike athletes originally set, two examples of the potential benefits of banned shoes came in recent triathlons.
At the Kona World Ironman Championships in October 2022, Norway’s Gustav Iden wore an On prototype that would be prohibited by World Athletics standards. At the time, triathletes were not subject to the World Athletics shoe ban rule. (World Triathlon has since updated their rules to support World Athletic regulations at the start of this year.) Iden ran a new Kona marathon record of 2:36:15 and credited the shoes with helping him in a postrace interview.
A few weeks later, Patrick Lange ran the fastest time ever in an Ironman marathon, clocking a blazing 2:30:32 at the Ironman Israel wearing the Adidas Prime X Strung, a banned running shoe.
While most evidence of the benefits of banned running shoes is anecdotal, research on cushioned shoes in general shows some advantages. For example, one small study of 32 participants published in April 2022, demonstrated that highly cushioned running shoes improved running performance, as shown by speed improvements and reduced muscle damage, compared to regular running shoes.
So, should you wear banned running shoes?
You might wonder if the World Athletics rules apply to all runners or just elites.
For those looking for a Boston qualifying time, the rules might apply to you more than others not chasing a place on the starting line in Hopkinton. “All athletes, regardless if they are competing in the professional or open races, are expected to wear footwear which conforms to current World Athletics rules and standards,” Chris Lotsbom, the communications and media manager for the Boston Marathon tells Runner’s World. But he also adds: “To my knowledge the B.A.A. has not refused entry [to the Boston Marathon] to a runner based on wearing prohibited footwear in the past.”
As for your local road race, if it’s a USA Track & Field-certified course, then the same rule would apply because USATF complies with World Athletics shoe regulations. (Keep in mind, these rules do not extend to high school or college races.)
It’s important to note that there aren’t many reports of people getting disqualified because of banned shoes. And if you’re not going for a BQ, it probably doesn’t matter if you’re wearing banned shoes—unless maybe you plan to get a place on the podium.
When you’re buying shoes, every physical therapist and specialty running shop owner will say that the best running shoe is the running shoe that fits and feels the most comfortable. If a banned running shoe checks those boxes, then by all means, buy it.
As for whether you save them just for training runs, or decide to race in them, it’s about weighing the risk and reward. Just know that technically, like professionals, you could get disqualified if you race certified courses in them. Will that actually happen? Not necessarily. After all, headphones are banned, too, but you won’t see someone get DQ’d for rocking out.
Cory Smith is a running coach and journalist specializing in running and fitness-related content and gear reviews. He is the founder of Run Your Personal Best, an online running coaching business that has helped hundreds of runners achieve personal bests in distances ranging from 800 meters to 100 miles. Cory holds a USA Track & Field Level 1 and 2 Endurance Certification and was the former Head Cross Country/Track Coach at Penn State Brandywine. Over his running career, Cory has held three Maryland state records, was a two-time National Championship qualifier while at Villanova University, and holds personal bests of 4:03 in the mile and an 8:05 in the 3K.
