World Athletics has stopped short of a total ban on Nike’s controversial Vaporfly range, as it announced significant changes to its rules.

The measures include outlawing some variants of the Vaporfly running shoes and the introduction of strict limits to the technology developed for any future shoes used in elite competition.

The sport’s governing body (WA) said on Friday that with immediate effect, road shoes must have soles no thicker than 40mm and not contain more than one rigid, embedded plate.

The ‘AlphaFly’ prototype shoes used by Eliud Kipchoge to run the first sub-two hour marathon and the ‘Next%’ variant worn by fellow Kenyan Brigid Kosgei to smash the women’s marathon world record both contained carbon plates inside thick, ultra-compressed foam, said by Nike to help improve running economy by up to four per cent.

The new rules also state that, from April 30, any shoe used in competition must have been generally available to the public for four months – putting paid to the use by Nike and others of prototypes by its athletes in major races.

Tweet from @WorldAthletics

There will also be new rules governing the construction of track spikes.

“It is not our job to regulate the entire sports shoe market but it is our duty to preserve the integrity of elite competition by ensuring that the shoes worn by elite athletes in competition do not offer any unfair assistance or advantage,” WA President Sebastian Coe said in a statement.

“As we enter the Olympic year, we don’t believe we can rule out shoes that have been generally available for a considerable period of time, but we can draw a line by prohibiting the use of shoes that go further than what is currently on the market while we investigate further.

“I believe these new rules strike the right balance by offering certainty to athletes and manufacturers as they prepare for Tokyo 2020, while addressing the concerns that have been raised about shoe technology.”

-with AAP