Quick Answer
Running shoes are banned from sanctioned marathons if they have a midsole over 40mm or more than one rigid plate. Banned models include Adidas Prime X, Asics Superblast, Hoka Skyward X, New Balance SuperComp Trainer, and Saucony Kinvara Pro. Check your shoes at the World Athletics approved shoe list before race day. Community races generally don’t enforce these rules.The Rules: What Makes a Shoe Illegal
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| Rule | Road Races (Marathon, Half, 10K) | Track Events |
|---|---|---|
| Maximum stack height | 40mm | 20mm (up to 800m) / 25mm (over 800m) |
| Maximum plates | 1 rigid embedded plate | 1 rigid embedded plate |
| Retail availability | Must be available for purchase 4+ months before competition | Same |
| Prototypes | Banned — no custom or unreleased shoes | Banned |
These rules were introduced by World Athletics in January 2020 after Nike’s Vaporfly line triggered a wave of record-breaking performances that raised fairness concerns. The 40mm limit and single-plate rule were designed to allow innovation while preventing shoes from becoming mechanical aids.
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Banned Running Shoe Models (2025/2026)
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| Shoe | Brand | Stack Height | Reason Banned |
|---|---|---|---|
| Adidas Prime X / Prime X 2 Strung | Adidas | ~50mm | Exceeds 40mm, multiple carbon plates |
| Asics Superblast | Asics | ~45mm | Exceeds 40mm stack height |
| Hoka Skyward X | Hoka | ~45mm | Exceeds 40mm stack height |
| New Balance SuperComp Trainer | New Balance | ~42mm | Exceeds 40mm stack height |
| Saucony Kinvara Pro | Saucony | ~42mm | Exceeds 40mm, multi-plate construction |
| Nike Alphafly (original prototype) | Nike | >40mm | Exceeded 40mm, multiple plates, prototype |
| Nike Vaporfly Elite (prototype) | Nike | >40mm | Prototype not available at retail |
Note: The retail Nike Vaporfly NEXT% and Nike Alphafly NEXT% 2 are legal — they meet the 40mm limit with a single plate. The banned models are the original prototypes and “super trainer” versions that exceed the limits.
This list changes as manufacturers release new models. Always check the World Athletics approved shoe list before race day.
Legal vs Banned: Popular Race Shoes Compared
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| Shoe | Stack Height | Plates | Race Legal? |
|---|---|---|---|
| Nike Vaporfly NEXT% 3 | ~40mm | 1 carbon | ✅ Yes |
| Nike Alphafly NEXT% 2 | ~40mm | 1 carbon | ✅ Yes |
| Adidas Adios Pro 3 | ~39mm | 1 carbon | ✅ Yes |
| Saucony Endorphin Pro 4 | ~40mm | 1 carbon | ✅ Yes |
| Asics Metaspeed Sky+ | ~40mm | 1 carbon | ✅ Yes |
| Hoka Rocket X 2 | ~39mm | 1 carbon | ✅ Yes |
| Adidas Prime X 2 | ~50mm | 2 carbon | ❌ Banned |
| Asics Superblast | ~45mm | — | ❌ Banned |
| Saucony Kinvara Pro | ~42mm | Multi | ❌ Banned |
The difference between legal and banned often comes down to 2–5mm of midsole foam. Manufacturers design race shoes right at the 40mm limit to maximise performance within the rules.
Where Do These Rules Apply?
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| Event Type | Rules Enforced? | Notes |
|---|---|---|
| World Athletics sanctioned races | ✅ Yes | All World Marathon Majors, championship events |
| Ironman / Ironman 70.3 | ✅ Yes | Same 40mm/single-plate rules for run leg |
| NCAA track & field | ✅ Yes | Enforced for collegiate competition |
| Boston/Chicago/NYC qualifying races | ⚠️ Varies | Qualifying times may not be accepted if shoes non-compliant |
| Community fun runs / parkrun | ❌ No | Wear whatever you want |
| Trail races | ❌ No | No stack height restrictions for mountain/trail events |
If you’re a recreational runner doing a local 10K or parkrun, these rules don’t affect you. But if you’re chasing a qualifying time, an age-group award, or racing in a sanctioned event, check your shoes.
How to Check If Your Shoes Are Legal
Step 1: Visit the World Athletics approved shoe list and search for your exact shoe model. If it appears, it’s legal.
Step 2: If you can’t find your model, check the midsole stack height. Anything over 40mm for road events is non-compliant. Most manufacturers list this in the shoe specifications.
Step 3: Confirm the shoe has been available at retail for at least 4 months. Brand-new releases may not yet be approved even if they meet the physical requirements.
Step 4: When in doubt, contact the race organiser. They can confirm which rules apply to their specific event.
Why Super Shoes Changed Everything
The controversy started with the Nike Vaporfly 4% in 2017. Research showed it reduced the energy cost of running by approximately 4% compared to traditional racing flats — a massive advantage at the elite level. Marathon world records began falling at an unprecedented rate, and other brands rushed to develop their own carbon-plated “super shoes.”
World Athletics responded in 2020 with the 40mm/single-plate rule. The goal wasn’t to stop innovation — it was to set a boundary. Since then, manufacturers have continued to improve shoes within the rules, and most current race-legal super shoes still deliver significant performance benefits over older designs. The banned “super trainers” are simply the models that push beyond those boundaries.
For a deeper look at how shoe technology has changed marathon racing, see our article on how much running shoes weigh and why weight matters for race performance.
FAQ: Banned Running Shoes
What shoes are banned from marathons?
Any shoe with a midsole over 40mm or more than one rigid plate. Specific banned models include Adidas Prime X, Asics Superblast, Hoka Skyward X, NB SuperComp Trainer, and Saucony Kinvara Pro.
What are the World Athletics shoe rules?
Road races: 40mm max stack height, 1 rigid plate max, 4-month retail availability. Track: 20–25mm depending on event distance.
Do the rules apply to recreational runners?
Not at community races or parkruns. They apply at sanctioned events, Ironman, NCAA, and when chasing qualifying times.
Why were Nike Vaporflys banned?
The original prototype exceeded 40mm with multiple plates. The retail Vaporfly NEXT% is legal — it meets the rules.
How do I check if my shoes are legal?
Search the World Athletics approved shoe list. If your model appears, it’s compliant.
Know the Rules, Race With Confidence
The shoe rules exist to keep racing fair while still allowing the technology that makes modern running shoes faster and more comfortable than ever. Check the list, know your shoe’s stack height, and show up to race day without any doubt about your gear.
The right shoes are step one. The right training plan is step two. Our Running Coaching builds a personalised marathon programme around your goals, schedule, and current fitness — from first marathon to sub-3.
Find Your Next Running Race
Ready to put your training to the test? Here are some upcoming running events matched to this article.
