Nike has launched a mass market version of its controversial Alphafly prototype shoe that it says complies with new World Athletics rules.
World Athletics has insisted it will not let running-shoe technology spiral further out of control despite the release of another “gamechanging” Nike marathon shoe on Wednesday.
Track and field’s governing body also rejected claims that the US company might have had advanced warning of its new regulations, announced last Friday, after the company’s new Air Zoom Alphafly Next% with a 39.5mm heel slipped just inside the new limit of 40mm.
The prototype shoes worn by Eliud Kipchoge when the Kenyan became the first athlete to run a marathon in under two hours in October do not meet these restrictions.
A World Athletics spokesperson told the Guardian: “We spoke to several shoe companies, including Nike, a few days before we released our new shoe regulations to let them know what we were planning. But that was the extent of it.”
“We are now conducting detailed scientific research that will be finished this year on all the new shoes on the market to determine the extent to which they can improve performance. If in the process of that research we found that a certain shoe gave too much energy return compared to others on the market, say, we would look at our regulations again”, the spokesperson said.