LONDON (Reuters) - Nike Vaporfly shoes used to run the world’s first sub-two hour marathon will be banned from professional sport under a landmark decision on Friday that also allows currently sold versions of the high-tech shoes to be used in the Olympics.

FILE PHOTO: Athletics - Dubai Marathon - Dubai, United Arab Emirates - January 24, 2020 General view of an athlete wearing the Nike Vaporfly shoes REUTERS/Christopher Pike/File Photo

The first-ever shoe ban by World Athletics (WA), the sport’s governing body, addresses concerns that technology advances are giving athletes an unfair and unnatural advantage. It limits future use of carbon fibre plates and some track spikes but stopped short of outlawing the Vaporfly models that have helped re-write the record books for elites and amateurs alike.

Prototype variants of the Vaporfly used by Eliud Kipchoge to run the first sub-two hour marathon and by fellow Kenyan Brigid Kosgei to smash the women’s marathon world record were both reported to contain triple carbon plates inside thick, ultra-compressed foam, said by Nike to help improve running economy by up to four percent. Those have been banned and from April 30 any future version, of any shoe, must have been available to the general public for four months before being allowed in elite competition. That will put paid to the use by Nike and others of prototypes by their athletes in major races.

Nike Inc NKE.N unleashed the Vaporfly in 2016 and various versions have quickly come to dominate the elite and "serious recreational" side of road running. The distinctive pink and green footwear, which cost around $250 and have a lifespan of only around 200 miles, is now widespread throughout the fields of every major race.

Kipchoge and other leading athletes have welcomed the shoes as a natural technological advance, but others say they have gone too far, with Yannis Pitsiladis, a professor of sport and exercise science at Britain’s Brighton University, calling them “technological doping”.

“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 on Friday.

World Athletics said any records set under the previous rules will stand.

“We can draw a line by prohibiting the use of shoes that go further than what is currently on the market,” Coe said. “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.”

The new rules state that road shoes must have soles no thicker than 40mm and not contain more than one rigid, embedded plate.

The controversy could provide a boost for athletic equipment maker Nike, burnishing the Vaporfly’s reputation among amateurs not affected by the ruling.

“If anything this probably brings more excitement around the product,” Edward Jones analyst Brian Yarbrough said. “Over two-thirds of footwear that is bought, is bought for fashion purposes.”

WA will establish an expert working group to guide future research into shoe technology and to assess new shoes that emerge on the market.

Nike did not immediately respond to Reuters’ request for comment on the decision.

‘SECRET WEAPON’

Marathon superstar Kipchoge has been the Vaporfly’s flagbearer, wearing them to set a world record, win the 2016 Olympic title and then, in an advanced version not available to the public, go under two hours in an unofficial marathon.

Kosgei ran 2:14.04 in last year’s Chicago Marathon, taking 81 seconds off Briton Paula Radcliffe’s 16-year-old women’s marathon world record and making her almost three minutes faster than any other woman in history.

Vaporflys have featured in several other records in the last three years and athletes wearing them took 31 of the 36 top-three finishes in the Marathon Majors series last year.

Nike says the shoes have “a built-in secret weapon that provides a propulsive sensation”.

Other manufacturers have also released, or are developing, their own carbon-insoled shoes, but WA’s ruling would now appear to have put the brakes on.

WA’s action echoes that of swimming’ s governing body, which a decade ago banned Speedo’s record-smashing LZR speed suit.

Kosgei, however, was unmoved when asked by Reuters about the ban. “The shoes did not have legs to run, it is the power and energy of an athlete,” she said. “Not every athlete who wore the shoes ran a world record.”