Nike’s controversial marathon running sneaker is facing a possible ban from the sport’s governing body.
World Athletics (formerly the International Association of Athletics Federations or IAAF) is said to be mulling whether to block the cutting-edge footwear from the competition after Kenyan marathon runners Eliud Kipchoge and Brigid Kosgei, in addition to others, set unofficial and official records in 2019 while wearing the Vaporfly Next% shoes.
While the London Times reports that the group will introduce rules banning the sneaker, a story by The Guardian states that rather than an outright ban, World Athletics will limit the role of the shoe’s key elements—carbon fiber plates and advanced foam technology—in future competition footwear.
Vaporfly Next% running shoes have become nearly universal on the marathon and racing circuits, overwhelming the competition and allowing runners like Kipchoge and Kosgei to set personal bests and world records without dramatically changing their training routines.
Nike’s Vaporfly racing shoes sport extremely thick midsoles, outfitted with carbon plates that function as springs when a runner puts their weight down. An aerodynamic, offset construction combined with this high level of energy return works to reduce the amount of force runners need to propel themselves. Vaporfly’s ability to increase a runner’s speed and endurance even informs the naming of each model, with the Vaporfly 4% seen improving running times by four percent, for example.
In October, Kipchoge ran a marathon in under two hours, a feat never before accomplished. Although this was not an official time in an official competition, as it took place under ideal conditions and Nike supervision, the running world and World Athletics took notice.
“The challenge for the IAAF is to find the right balance in the technical rules between encouraging the development and use of new technologies in athletics and the preservation of the fundamental characteristics of the sport: accessibility, universality and fairness,” a spokesperson told ESPN.com at the time.
The Vaporfly doesn’t actually affect Kipchoge’s speed during a race so much as his ability to recover from training and racing and is therefore not an unfair advantage on the track, the athlete’s camp told ESPN.com. However, some also point to the fact that the model Kiphchoge wore when breaking the unofficial record was a prototype variant called the Alphafly currently unavailable to the general public.
Asics, which was largely pushed out of the Tokyo marathon by the Vaporfly’s overwhelming popularity with runners, saw its stock tick up by 8 percent on the Tokyo stock exchange immediately following the news of a possible ban.