What Stack Height Is Race Legal?
World Athletics caps sole stack height at 40mm for shoes worn in its sanctioned road running and race walking events, and generally limits competition shoes to one rigid embedded plate. This rule targets elite/sanctioned competition — it does not affect recreational training or most local races.
The one thing to know: Stack height is the total cushioning thickness under the foot, and World Athletics caps it at 40mm for shoes worn in its road running and race walking events (also limiting most competition shoes to one rigid plate). This rule applies to elite/sanctioned competition, not to training or to recreational runners in a local race — but it's the reference point for the 'is this shoe race legal' question people ask about max-stack shoes.
Who the rule actually applies to
The 40mm limit and one-plate rule are World Athletics competition regulations, enforced in the context of sanctioned elite competition (major marathons, championship races, and similar events run under World Athletics rules). A recreational runner at a local 5K or marathon is generally not measured or disqualified for stack height — the rule matters for athletes competing for a leading position under those specific governing rules, not as a general product-safety or legality standard for consumer footwear.
Checking a shoe's stack height
Manufacturers typically publish stack height (heel and forefoot, in millimeters) in a shoe's spec sheet or product page. If race legality under sanctioned rules specifically matters to you, compare the published number against the current World Athletics limit rather than assuming based on a shoe's marketing category (like "max cushion").
This page summarizes a competition rule; it is not legal advice or a guarantee of any specific race's enforcement practice.
Frequently Asked Questions
World Athletics caps sole stack height at 40mm for shoes worn in its sanctioned road running and race walking events. Most competition shoes are also limited to one rigid embedded plate.
Almost certainly not for enforcement purposes. The rule targets elite/sanctioned competition — recreational runners at local races generally aren't checked for stack height, and wearing a shoe over 40mm won't get you disqualified or stopped from running unless you're competing for a leading position under World Athletics rules.
Not always — many max-cushion trainers sit in the high-30s to low-40s range and some exceed 40mm, but stack height varies by specific model. Check a shoe's published stack spec if race legality matters to you.
Yes — World Athletics also generally limits competition shoes to one rigid plate (of any material) running the full or partial length of the shoe, separate from the stack-height limit.
World Athletics has periodically revisited and clarified its shoe regulations since introducing the 40mm limit, including adjustments to track-shoe rules; the 40mm road limit itself has remained a stable reference point. Always check World Athletics' current published rules for the latest detail if racing under sanctioned rules matters to you.