What Triathletes Need to Know About the New Rules Governing Nike’s Speedy Shoes

World Athletics (formerly IAAF) last week announced its much-anticipated “amended” shoe rules. In doing so, the governing body for running provided several answers for those concerned about any potential unfair advantage from Nike’s line of speedy super shoes—and raised a few more questions.

What do the new shoe rules say?

The new rule, to take effect immediately, requires that running shoes have a maximum midsole thickness of 40mm and no more than one stiff carbon plate. This rule appears to grandfather in the Nike Vaporfly Next%s, which has been a popular shoe of choice among elite marathoners and many top triathletes.

However, the new rule does appear to disqualify the prototype version of the Nike Alphafly shoe that Eliud Kipchoge wore last October to run his 1:59:40 exhibition marathon in Vienna. That shoe is widely believed to have a midsole exceeding 40mm and more than one plate—though Nike has not publicly revealed details of the prototype shoes.

In running events that are governed by World Athletics and the International Olympic Committee, officials will have the right to confiscate, post-finish line, any shoes they believe to be questionable. These shoes could then be measured for midsole thickness, and presumably sawn in half to assess the number of plates.

The rules also state that after April 30, 2020, no shoe can be used in competition unless it “has been available for purchase by any athlete on the open retail market” for at least four months. This means that for any shoes to be worn in the Tokyo Olympics they must be available by about March 15. A shoe that does not meet this criterion will be deemed a “prototype” and prototypes will not be legal.

Why were people so upset about Nike’s 4%s and Next%s in the first place?

Nike’s line of Vaporfly 4%s and later the Next%s appeared to give runners an advantage. Whether that advantage is due to the carbon plate sandwiched between cushioning foam or due to the specific type of foam Nike created and copyrighted has been hotly debated. But the combo was meant to create greater efficiency via some level of energy return—allowing you to run easier at the same pace and ultimately run faster for the same effort

World Athletic’s previous Competition Rule #143 5.B. stated that no shoe can provide an “unfair” advantage and that “any type of shoe used must be reasonably available to all.” Several runners who aren’t Nike-sponsored athletes have been extremely critical about the use of the shoes, arguing they violated the spirit if not the letter of the rules.

Those on the other side of the argument argue that “unfair” simply means “no wheels, no motors.” Nike proponents have suggested any shoe company could create shoes with similarly thick foam and carbon plates—and in fact many companies have begun to unveil their own prototypes. 

While the angst around these rulings was high in the running community, there’s been less controversy among triathletes. Up to this point, Nike is fairly uninvolved financially in triathlon from a sponsorship standpoint. Yet, in last year’s Ironman World Championship pro field, four out of the top 10 men and five out of the top 10 women (including the entire women’s podium) were wearing some version of Nike’s 4% or Next% shoes. Most of these pros simply went out and purchased the shoes—just like many amateur triathletes can and have.

Are the shoes legal to race in now?

Yes, for now. The 4%s and Next%s, popular among triathletes, will be legal to wear as they fall within the new guidelines. Nike (and other shoe companies), though, will be limited from taking that technology too much further or allowing pro runners to race in prototypes. 

Triathletes will also have a new option. Right on the heels of the announced rules, Nike this week unveiled a “legal” version of the newly-illegal prototype shoe worn in Kipchoge’s sub-2:00 marathon. The Nike Air Zoom Alphafly Next% is designed to fall within the guidelines of the new rules. The shoe, which is the final market version of that prototype, features one full-length carbon fiber plate, cushioning that falls just within the 40mm guidelines, and Nike Air Zoom Pods—something that was not used with the 4% and Next%. The shoe is part of a line of products announced, including the Nike Air Zoom Tempo Next% and Nike Air Zoom Tempo Next% FlyEase, which Nike says are meant to be complementary training shoes.

Nike told Runner’s World that a limited number of the Alphafly Next%s will be available to Nike+ members on the day of the Olympic Marathon Trials on Feb. 29. Wider distribution is expected to come this summer.

How will this affect triathlon?

There are plenty of regulations around wetsuits, bikes, and helmets, but both USA Triathlon (USAT) and the International Triathlon Union (ITU) do not currently have any rules when it comes to running shoes—but that doesn’t mean they won’t be implementing these new rules.

“At the moment, ITU doesn’t have any rules about shoes. And where we have no specific rules (for running), IAAF rules apply” the ITU told us in late January. “It would not be [ITU’s] own ban since we don’t have rules on this matter, it would be—if the case arrives—us following IAAF rules.” [Note: World Athletics formerly was known as IAAF, meaning the ITU would follow the new World Athletics rules.]

When asked, an Ironman spokeperson told us, “For this we will have to defer you to the ITU and the federations.”

Since Ironman follows USAT (or the given country’s federation) rules and USAT follows ITU rules and the ITU is deferring to the World Athletics, these same rules will like apply to most triathlon races. But because the rules allow for the 4%s, the Next %s, and the Alphafly Next%s to be worn in competition, triathletes needs should be met. So you probably don’t need to worry about wearing the bright neon shoes at your next race. The same applies to the new carbon-plated shoes being released from Brooks, Saucony, Hoka, Asics, and New Balance.

One caveat: Triathletes could be restricted from using prototypes in competition. For example, Jan Frodeno did wear a prototype Asics shoe during his record-breaking Ironman World Championship victory. But it probably wasn’t just the shoes that got him there.