The world's fastest marathon runner, Eliud Kipchoge, is hoping that a new running shoe designed and developed by Nike in just 4 months will propel him to victory at the 2018 London Marathon this week.
The new shoe is actually a variant of the shoe he wore for the Breaking2 event that saw him run the 26.2 miles in 2:00:25. But features a brand new upper design that has been 3D printed rather than weaved using Nike's popular Flyknit technology.
"We've always used 3D printing to refine the design, but one of our designers saw that there was huge potential with the material and design process beyond prototyping," explains Nike Running's global footwear designer Bret Schoolmeester to Pocket-lint as he showcased the new shoe to be worn by Kipchoge and Sir Mo Farah for the race.
The decision to try and improve on the Nike Zoom Vaporfly Elite came following a run by Kipchoge in the 2017 Berlin marathon.
Wet conditions meant the Flyknit material of the shoe absorbed water and that water wasn't able to evaporate, so it added weight. Kipchoge turned to Schoolmeester and his design team to make something better in time for London.
"We printed a shoe and then I thought, I'm just going to run in these and see what happens. It fit amazing and felt really good, but quickly fell apart by the end of the run. We knew there was still work to be done, but all of us collectively in the team said there was huge potential here, let's keep pushing forward, and one of the big advantages was to quickly turn around iterations and fix the problems as we went."
Using a rapid-fire prototyping phase, the Nike Running design team went through thousands of upper possibilities before hitting "print" on several variations for each prototype.
"We put a really small team of around three to four people on the project and told them to just create something as fast as they could to create a shoe by April that would be ready for the Boston and London Marathon."
The approach meant the design team was able to create the final version in a fraction of the time it would normally take.
"Designers made updates to the shoe in hours, with Kipchoge requesting tiny detail changes about tightness in specific areas as the shoe developed," added Schoolmeester.
The end result is the Nike Zoom Vaporfly Elite Flyprint, a shoe that weighs 169g and is 11g lighter than its Flyknit Breaking2 predecessor.
To make all this possible, Nike used 3D printing to create a new textile it is calling Nike Flyprint: the first 3D-printed textile upper in performance footwear.
At its most basic level, Nike Flyprint uppers are produced using a process similar to how many 3D printers in the home work by building up layers to create a three-dimensional shape.
The seamless upper is then thermally bonded to Flyknit elements, like the lace area for comfort, before being bonded to the sole to create the shoe.
Flyprint and Flyknit are what Nike call "additive technologies". That's printing the shoe either via a 3D printer or via weaving the yarn to a detailed level as with Flyknit.
It's by adopting these technologies that Nike's Schoolmeester says they've been able to create the new shoe:
"Computation design is fantastic because it allows us to push the limits of what our designers would normally come up with. But it's only good as what you are going to make with it at the end. If you can design a structure that you couldn't imagine but you can't build it, it just stays on your computer screen. This [the Nike Zoom Vaporfly Elite Flyprint] is our best example to date of computation design and computation manufacturing to amplify what's possible."
In terms of design, the advantage of Flyprint appears obvious. The 3D shoe can be created specifically for the athlete before being printed locally rather than in a factory half way around the world, but more importantly for Nike at this stage, that rapid iteration means testing and revision cycle times are trimmed significantly.
"We've found that working with athlete's fit is incredibly important. It might be that Eliud [Kipchoge] is asking us to tighten a part of the shoe to feel more secure, we can do that now!" Schoolmeester tells us excitedly. "Flyknit is all connected, the yarns are connected in one long yarn, where Flyprint allows us to make a change in a specific part of the shoe and for it to be only felt right at a set point. Better still we can create it, print it that day, and be testing within hours and if it doesn't work trying something else straight away."
With shoes being able to be created in less than 45 minutes you can see the appeal.
It's that appeal that means this, says Schoolmeester, is the way Nike will make all its running shoes for its elite runners programme going forward.
But it is not just elite athletes that will be getting access to the new shoe and the new technology. The Nike Zoom Vaporfly Elite Flyprint will be available in a very limited edition run for others to buy ahead of the London marathon.
"This isn't a one-off shoe. We've used this project to work out how to use Flyprint and now that we have we will look to see how we can make it commercially viable in a broader sense."
A consumer training version of the shoe, Nike tells Pocket-lint, will be available before the end of 2018.
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