Athletics body to tighten rules after Nike's Vaporfly helps records tumble

World Athletics are running the rule over whether to tighten regulations over Nike's controversial Vaporfly shoe, which is said to substantially improve performance but has been labeled by some as technological doping.

The sports governing body is expected to reveal the results of its investigation by the end of January, and in a statement to Reuters said that "there needs to be greater clarity on what is permissible in elite sport and in competitions."

The shoes in question have risen to prominence in recent months after a version were worn by Kenyan runner Eliud Kipchoge, when he became the first man to run a sub-two hour marathon in Vienna last year.

Kipchoge is a fan of the shoes and its technology that Nike calls "a built-in secret weapon."

Yannis Pitsiladis is a Professor of Sport and Exercise Science at the University of Brighton breaks down just how far ahead the Vaporfly is of its rivals.

(SOUNDBITE) (English) PROFESSOR OF SPORT AND EXERCISE SCIENCE AT THE UNIVERSITY OF BRIGHTON, PROFESSOR YANNIS PITSILADIS

"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. Nike's own data that they've published now has shown that some individuals, the benefit in economy is up to 6%. And remember, this is individuals that were testing the shoe, they weren't individuals that the shoe was designed for."

Other manufacturers have also released, or are developing, their own carbon-insoled shoes to rival the $250 Vaporflys, but they are all playing catch-up in this arms race for feet.

In 2008, Speedo delivered its LZR speed suit which helped swimmers claim a host of world records before it was banned.

Other technological leaps, such as skinsuits in skiing, hinged blades in speed skating and aero bars and disc wheels in cycling, survived to become standard equipment.