By Amy Tennery
ATLANTA (Reuters) - A debate over Nike's record-breaking distance footwear raged on ahead of Saturday's U.S. Olympic marathon trials, as the shoe's buzz-worthy technology continued to raise questions over whether it offered an unfair advantage to runners.
The Nike Vaporfly shoe captured the spotlight in October when Eliud Kipchoge broke the two-hour marathon barrier wearing a pair, and various versions of it have featured in other record-smashing runs since.
"It's hard to argue that they do not provide an advantage just because of the 500 women who are running, 480 are going to be wearing Vaporflys," said Kellyn Taylor, a marathoner sponsored by HOKA ONE ONE who is seen as a top contender in the women's field.
"Technology is important. I think that it should always be advancing, but I do think there's a cap on it," said Taylor, who came sixth in the 2016 trials. "I think the question is, 'Have we reached that?'"
While many of the leading contenders, like Taylor, are bound by sponsorship deals to wear specific brands on race day, unsponsored athletes such as Jake Riley, who boasts the fifth-fasted qualifying time in the men's field, are free to run in any approved shoe.
Riley played down rumors that he declined lucrative sponsorship deals to keep his independent status, telling reporters this week, "There was a little interest but not a ton, and so we decided to just keep the options open."
He plans to wear a pair of the carbon-plated Nikes on Saturday, as he did to compete in the Chicago Marathon in 2019, where he was the top-finishing American.
"The guys I was competing against were also wearing some sort of carbon fiber-plated shoe and I was able to compete against them and feel strong," Riley said. "It's more just (about) taking the playing field back to even."
Jared Ward, a Saucony athlete who placed sixth in Rio, echoed the frustrations of many of his fellow athletes that the shoe debate had become so central to their sport.
"One thing that we're not talking about with these shoes is some people are responders to them and some people are kind of not," said Ward. "One big thing we have left to answer in shoe technology is, 'Can we build a shoe for a specific runner, as opposed to a shoe that's better on average?'
"I'm excited for shoes to at least calm down enough that we can put the conversation back on the athletes running in the shoes."
Nike launched a new version of its Alphafly shoe earlier this month that complies with new rules introduced by the governing body that limit the use of carbon plates and sole thickness for elite races.
"We are pleased the Nike Zoom Vaporfly series and Nike Zoom Alphafly NEXT% remain legal," Nike said at the time. "We will continue our dialogue with World Athletics and the industry on new standards."
Other shoemakers such as HOKA and Brooks, which boast their own roster of top athletes competing on Saturday, have also embraced the use of carbon plates in some of their models.
Des Linden, the 2018 Boston Marathon winner, will wear a pair of Brooks' new Hyperion Elite 2 on Saturday as she aims to reach a record third straight Olympic marathon competition.
"I'm confident in the shoes I've had and I've done it before," said Linden. "I can't control what anyone else is wearing."
(Reporting By Amy Tennery; Editing by Daniel Wallis)