NEW YORK (Reuters) - A shoe debate is raging ahead of Sunday’s New York City Marathon after high-tech sneakers played starring roles in two of the biggest distance-running achievements this year.

FILE PHOTO: Runners race during the 2018 New York City Marathon in the Brooklyn borough of New York City, New York, U.S., November 4, 2018. REUTERS/Caitlin Ochs/File Photo

Eliud Kipchoge’s sub-two-hour marathon in Vienna and Brigid Kosgei’s record-breaking run at the Chicago Marathon last month brought the Nike Vaporfly shoes into focus, sparking heated debate over whether the hyper-advanced footwear gave an unfair advantage.

Shalane Flanagan, who won in New York in 2017, told Reuters the running community should “always question what’s going on” in her sport but said the debate should not overshadow individual performances.

“You could give the pair of shoes to Joe Shmo off the street – they can’t go run what Eliud ran or Brigid Kosgei,” said Flanagan, a Nike athlete who recently retired from competition and was consulted in the creation of the shoe.

“It’s up to other companies now to match the innovation or the IAAF needs to come in and say ‘we’re not having this innovation as part of our sport’,” the American added.

The International Association of Athletics Federations (IAAF) established a working group months before Kipchoge’s historic run to establish whether the shoes were fair and expects the group to report back before the end of the year.

“The challenge is striking a balance between spurring development of ‘new technologies’ while preserving ‘the fundamental characteristics of the sport’,” the association said in a statement.

IAAF rules state “shoes must not be constructed so as to give athletes any unfair assistance or advantage” and that “any type of shoe used must be reasonably available to all”.

Nike said they “respect the IAAF and the spirit of their rules” in the running sphere.

“The shoe that Brigid wore in Chicago is the Nike ZoomX Vaporfly NEXT%. In Vienna, Eliud wore a future version of the Nike Vaporfly that is currently unreleased,” a Nike spokesperson said. “However, a shoe is only one factor in a race, and Eliud’s incredible run should be acknowledged.”

Retired marathoner Meb Keflezighi, who won the New York City Marathon 10 years ago, told Reuters credit still belonged to the athletes despite high-tech advances.

“You’ve got to have the lungs, you’ve got to have put in the work and all that,” the Olympic silver medalist said. “If there’s a lot of aid at the end I’m pretty sure it will make a difference.”

Athletics is not the only sport to consider reining in the use of advanced technology in competition. In 2010, high-tech suits were banned from swimming amid a glut of broken records.

“It’s super frustrating that someone has an amazing race and we go ‘what are they wearing?’ It’s not just the athlete anymore,” 2018 Boston Marathon winner Des Linden told reporters in New York.

“It’s going to become – well, it is -- an arms race and it should be a foot race,” said Linden. “We should find out who (is) the best athlete and who can cover 26.2 (miles) better than the other person, not who has the newest, greatest technology.”