By Louisa Off, Anja Guder and Lori Ewing
LONDON, April 28 (Reuters) - Kite-surfing fabrics, car tyres and shortened shoelaces helped Kenyan Sabastian Sawe and Adidas crack the two‑hour marathon barrier.
When Sawe shattered one of athletics' most elusive barriers in storming to victory at the London Marathon in one hour 59 minutes and 30 seconds on Sunday, it did not come from just physiology and grit, but from design choices drawn from far beyond the course.
Sawe debuted Adidas' lightest‑ever racing
shoe, the Adizero Adios Pro Evo 3, designed to deliver marginal gains at the elite end of the sport -- and they were realised in full by Sawe on Sunday.
"It starts with the mentality of the athlete, the coach, and the team behind the product, which is: what can we do better? What is the 1% of every single detail that we can improve?" Patrick Nava, Adidas' general manager of running, told Reuters.
"And so we got to a product that is 97 grammes, which is 30% lighter than the previous iteration.
"We did four things. We worked on the outsole. We left traction only where you need it. We took it away where you don't. And worked together with (tyre manufacturer) Continental to create an extremely thin rubber piece."
The largest weight saving came in the foam, with Adidas cutting the weight of its Lightstrike Pro Evo foam by 50% from the previous version.
"We looked at other industries for inspiration for the upper," Nava said. "In this case, you have a material that is inspired by what you can find in kite-surfing, extremely light but also extremely durable."
Even the laces were redesigned and shortened, saving a further two to three grammes.
The result, Nava said, is a shoe that improves running economy by 1.6% compared with the already market‑leading Evo 2.
In elite marathoning, that margin is the difference between hovering around the sport's most stubborn barrier and finally smashing through it.
Commercially, Sawe's Evo 3 is not intended as a mass‑market product. Nava likened it to a Formula One car. An initial release on Monday of a few hundred pairs sold out online in two minutes, he said, with further limited drops planned in the coming weeks.
The broader objective, he said, is a cascade effect.
"In the second half of the year, we will come out with a more commercial version of the shoe," Nava said. "A lot of the technology will be very similar to what you see here."
SUPER SHOE BENEFITS
Sawe's victory comes more than a decade after Kenyan great Eliud Kipchoge wore an early, prototype version of Nike's Vaporfly to win the 2016 London Marathon, the first major marathon ever won in a super shoe.
But they made their big splash later that year at the Rio Olympics, with Nike's Vaporfly marking a turning point in distance running.
Geoff Burns, a sports researcher and engineer and a sports physiologist for the U.S. Olympic and Paralympic Committees, said the benefits of super shoes extend beyond the race itself.
"The first time I was running in them, my thought was: wow, this feels like cycling," he told Reuters in an interview from Colorado Springs. "Because of that curved plate, there's this like perpetuality to the motion that just feels like your legs are turning over more effortlessly or more naturally.
"That's one of the main benefits, you don't feel the trauma of running. That is probably a benefit that contributed to Sawe's world record, it's not just that the shoes are beneficial in taking time off the clock, it's that they do allow you to do more specific training, at marathon race speed or close to it."
If elite marathoners typically covered up to 140 miles a week, "these guys now are running 150 maybe 160 maybe even 170 miles a week," Burns said. "So they're doing a good bit more training, but more of that training is faster and close to marathon speeds, which is afforded by those shoes.
"97 grammes, I have socks that are heavier than that," he added.
On the heels of their remarkable achievement in London, focus has already shifted from celebration to what comes next, said Marc Makowski, Adidas' senior vice-president creative direction & innovation.
Within hours of the race, conversations had turned to whether the limits had truly been reached, or merely reset.
"The beauty was straight after the race on Sunday when we met with Sabastian," Makowski said. "He was quite vocal about the fact that he thinks he can run even faster. And I would say we just share that mindset with him.
"The beautiful thing about our job here is there is no real finish line. We're never done."
(Reporting by Lori Ewing, Louisa Off and Anja Guder; Writing by Lori Ewing; Editing by Christian Radnedge)
