Nike Vaporfly: 'Faster' running shoes will be allowed, World Athletics chiefs say

Athletes will be allowed to continue wearing controversial running shoes that can provide significantly better times, World Athletics (WA) has said.

Six months before the Tokyo Olympics, WA has decided to permit distance runners to use Nike Vaporflys, but it has banned the prototype Nike Alphafly shoes worn by Eliud Kipchoge to run the first sub-two hour marathon in October.

Athletes wearing the style of footwear, including Nike's latest Vaporfly, which the manufacturer claims help improve performance by up to 4%, took 31 of 36 top-three finishes in major marathons last year.

World Athletics president Sebastian Coe said: "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."

Under the new rules, with immediate effect, road shoes must have soles no thicker than 40mm and not contain more than one rigid, embedded plate.

For shoes with spikes, an additional plate or blade is allowed for the purpose of attaching the spikes, but the sole must be no thicker than 30mm.

The Alphaflys used by Kipchoge and his fellow Kenyan Brigid Kosgei when she set a new women's marathon world record time in October both contained triple carbon plates inside thick, ultra-compressed foam.

The Kenyan pair won the respective men's and women's races at last year's London Marathon.

From 30 April, any shoe used in competition must have been generally available to the public for four months - meaning an end to the use of prototypes such as the Alphafly, which are not on general sale.

Lord Coe said: "I believe these new rules strike the right balance by offering certainty to athletes and manufacturers as they prepare for the Tokyo 2020 Olympic Games."

But Yannis Pitsiladis, professor of sport and exercise science at the University of Brighton, was not convinced.

He warned that the shoe "is against the current rules of the sport" and could see the sport becoming "a race between the manufacturers, rather than a race between the athletes".

"All of us want to watch a Kenenisa Bekele, a Wilson Kipchang, an Eliud Kipchoge. What we don't want is put a shoe on me or you and you can run almost as fast as an Eliud Kipchoge can with a normal shoe... and that is where this has gone," he said.