You don’t have to stress about wearing ‘illegal’ running shoes during your race, and here’s why.
For most people, the idea of an ‘illegal’ running shoe is simply a myth. Yet, if you look at my social media feeds, you might think otherwise. A quick scroll reveals numerous videos from influencers using this term in a sensational way. One creator even features a series where he compares these so-called ‘illegal’ shoes against other models that are deemed ‘legal’.
But let’s pause for a moment—there’s something unsettling about this narrative, and it's been bothering me.
Let’s dive into the details together. Over the past five years, running shoes have experienced a significant transformation, both in terms of popularity and design. The running boom has made athletic footwear more sought after than ever before. At the same time, the actual height of these shoes has increased, with each new release showcasing thicker midsoles, which are often marketed as enhancing performance. This category is where the phrase ‘illegal shoe’ originates.
But what exactly makes these shoes ‘illegal’? They violate the regulations set by World Athletics, the governing body for athletics. According to their guidelines for road racing, which encompass events ranging from mile races to ultramarathons, shoes can only feature a sole height of up to 40mm and must include only one rigid structure, such as carbon plates or rods.
Most major running shoe brands adhere to these guidelines for their elite racing models. However, they seem to disregard these standards for other types, like everyday trainers, which have significantly increased in height in recent years. This disregard has led many runners to sport shoes that could technically be considered ‘illegal’.
Let me share some compelling evidence. As reported in Strava’s Year in Sport Report for 2025, the top three running shoes logged by users that year, along with their stack heights, include:
- Asics Novablast – 41.5mm
- Nike Pegasus – 37mm
- Hoka Clifton – 42mm
What’s interesting here is that only the Nike Pegasus falls below the ‘legal’ height limit. These so-called ‘illegal’ shoes are not contraband; they are simply the beloved trainers that many casual runners, including perhaps your uncle, wear on leisurely jogs. You might even wear them yourself, and that’s perfectly acceptable.
Whether you're gearing up for a local 5K or preparing for a prestigious event like the Abbott World Major Marathons, the chances of being disqualified for sporting ‘illegal’ shoes are exceedingly low. I participated in the New York Half Marathon last year wearing the Asics Superblast 2, which has a 45mm stack height. This year, I tackled the Big Sur Marathon while outfitted in the Hoka Skyward X, boasting a stack height of 48mm, with no repercussions whatsoever. Many runners can attest to similar experiences. In reality, these regulations primarily target elite athletes who compete in different heats and are subject to drug testing—concerns that average participants need not worry about.
To be thorough, I reached out to the New York Road Runners (NYRR)—the organization responsible for the New York City Marathon and the half marathon I ran last year. A representative confirmed that while they enforce World Athletics rules at their major events, they evaluate potential violations on a case-by-case basis. Interestingly, last year, no one was disqualified for shoe-related infractions.
That said, it’s worth noting that professional athletes have faced disqualifications due to shoe rule violations. Events like triathlons and Ironman competitions tend to have stricter regulations, with Ironman even listing specific shoe models that are banned from use in competition.
Although I believe that the hype surrounding ‘illegal’ shoes is largely driven by social media, it’s still wise to be cautious about the footwear you choose. Shoes with high stacks can sometimes lead to instability and may impact your running form, so understanding how to adjust to them is essential.
Dr. Mark Mendeszoon, a board-certified podiatrist and surgeon at Precision Orthopaedic Specialties in Ohio, explains, "It’s an adjustment, like getting braces on your teeth. You have to learn slowly." He suggests breaking in new shoes by wearing them around your home first, then emphasizing cross-training and recovery once you hit the pavement. "With all that foam and stack height, it’s going to kind of shorten your Achilles," he adds. “So work on Achilles flexibility and stretching afterward.”
In summary, if you’re genuinely concerned about ‘illegal’ running shoes, you probably already possess the knowledge and awareness necessary. And chances are, you’re not among those runfluencers creating buzz around the term.
