On Sunday, the Kenyan runner Geoffrey Kamworor won the New York City Marathon, completing the course in 2 hours, 8 minutes, 13 seconds.  Last month, Eliud Kipchoge Nike Air Max 95 Femme completed a marathon in under two hours — Adidas Ultra Boost Herren the shortest time ever — but the feat didn't officially count as a world record.Kamworor and Kipchoge both compete in Nike Vaporfly shoes, which some research suggests gives runners more energetic efficiencies.The International Association of Athletics Federations Nike Air VaporMax Damen is looking into whether the Vaporfly sneakers confer an unfair advantage.Visit www.palmyreroigt.fr Business Insider's homepage for more stories.On Sunday, Geoffrey Kamworor won the New York City Marathon for the second time in three years.His time — 2 hours, 8 minutes, 13 seconds in the Nike Air Vapormax Femme men's event — was a mere seven minutes above the world Nike Air Max 97 Dames record and less than 10 minutes behind the fastest marathon time ever recorded.

"From the start of the race, I was feeling OK," Kamworor said in a news release. "I was comfortable. I prepared very well to run this Adidas Superstar Dames marathon. Throughout the last few meters, Adidas NMD Womens the pace was somewhat high, and it wasn't a problem for me. That's when I decided to pull  away."Kamworor, who holds the world record in the half-marathon distance, won the New York City Marathon in 2017 and came in third last year.After he crossed the finish line on Nike Air Max 90 DamesSunday, the 26-year-old runner was greeted by fellow Kenyan marathoner Adidas ZX Flux Dames Eliud Kipchoge, who's also Kamworor's training mate. Kipchoge ran the first sub-two-hour marathon (the fastest ever recorded) last month in Vienna.

Both runners share a preference for Nike's Vaporfly Nike Air Max 90 Womens 4% sneaker.Kamworor wore them in New York on Sunday Nike Air Max 95 Femme — along with many other elite runners, as is clear in the photo below (they're bright pink) — and Kipchoge wore them in his history-making Vienna marathon. The three medalists in the men's marathon at the 2016 Summer Olympics also wore a Vaporfly prototype.Adidas NMD Dames But some runners say the footwear confers an unfair advantage.Kipchoge already Nike Air Max 90 Mujer Rosa holds the world record marathon time: 2 hours, 1 minute, 39 seconds. He clocked that in the Berlin marathon last year, where he also wore Vaporflys.In fact, according to The New York Times,  the five fastest marathon times ever recorded were all achieved Adidas ZX Flux Femme by male runners wearing Nike Vaporfly shoes.