World Athletics has cleared distance runners to keep wearing a favoured Nike design even though it acknowledged that shoe technology poses a risk to the sport.
The governing body published updated guidelines which limited the use of prototype shoes like Nike’s high-tech ‘Alphafly’ style worn in a sub-two hour marathon run by Eliud Kipchoge in Vienna in October.
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Independent research showed “sufficient evidence to raise concerns that the integrity of the sport might be threatened by the recent developments in shoe technology,” the Monaco-based governing body said.
An expert working group will be created to assess new shoes entering the market.
Still, the more established Nike style called ‘Vaporfly’, increasingly favoured by top marathon runners, can be worn.
World Athletics set a guideline taking effect on April 30 that a shoe must have been available to buy for at least four months to be eligible for use in competition.
“If a shoe is not openly available to all then it will be deemed a prototype and use of it in competition will not be permitted,” the statement said.
The Tokyo Olympics open in just under six months.
“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,” World Athletics president Sebastian Coe said.
“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 the Tokyo 2020 Olympic Games.”
Kipchoge’s specific design not allowed
The governing body announced an immediate "indefinite moratorium" on any shoe with a sole thicker than 40 millimetres, or 30mm for the sole on shoes with spikes.
Also subject to the moratorium will be shoes with more than one "rigid embedded plate or blade that runs either the full length or only part of the length of the shoe".
Nike's Alphafly bespoke shoe is widely reported to feature three carbon fibre plates.
World Athletics did not mention the Nike shoes in its news release on Friday, or say whether Kipchoge's world record would remain in the record books, and did not reply to requests for comment.
The new regulations will allow for modification of shoes but only for cosmetic or medical reasons.
As well as Kipchoge's historic achievement in 2019, which was not an officially ratified record, his fellow Kenyan Brigid Kosgei set a world record for the women's marathon also in Nike shoes.
It is not known whether the Nike Vaporfly shoes that Kosgei wore would be allowed under the specifications provided by World Athletics, or whether the shoes were modified.
According to The Times, Nike plans to commercially release an Alphafly shoe that will meet the new guidelines.