London Marathon 2018: Why Nike turned to 3D printing to make the lightest possible trainer for Eliud Kipchoge and Mo Farah

 
Joe Hall
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The finished product: After months of trial and error, Kipchoge will race in the Zoom Vaporfly Elite Flyprint in London this Sunday (Source: Nike)

The American track and field coach and co-founder of Nike Bill Bowerman summed up his work by telling athletes: “God determines how fast you’re going to run; I can only help with the mechanics.”

Olympic champion Eliud Kipchoge will be the latest beneficiary of those mechanics at this weekend’s London Marathon when he pulls on the world’s first 3D printed performance running shoe, unveiled this week by the sportswear giant.

Kipchoge, 33, is returning to a race that he won in 2015 and 2016, having skipped London last year in favour of focusing on becoming the first athlete to run a marathon in under two hours at Nike’s #Breaking2 showcase.

To aid his sub-two hour goal, the company created an ultra-lightweight running shoe boasting a top-secret, more responsive type of foam in the midsole and a steeper design under foot to improve efficiency.

Kipchoge narrowly missed his target, so ahead of this year’s Marathon Majors the sneaker scientists returned to the lab to hone their design. The results is the Zoom Vaporfly Elite Flyprint, and they insist it is no mere gimmick.


(Source: Nike)

Kipchoge provided constant feedback for the designers of the shoe (Source: Nike)

“If you don’t have a good answer to that then it’s just puffery or innovation for innovation’s sake,” Nike’s senior director for running footwear, Bret Schoolmeester, told City A.M.

Read more: How much prize money do London Marathon winners receive?

“The athletes don’t align to our latest and greatest unless it really works. Our athletes will not risk their key career moments for something just because it’s on Nike’s marketing map.”

Having revamped the midsole — the big soft foam part of your trainer between its canvas top and rubber bottom — attention turned to the upper, where Schoolmeester’s team thought enough weight could be taken out to make a significant difference to the marathon runner such as Kipchoge, Kenenisa Bekele or Mo Farah, who will also be wearing it on Sunday.

And that’s where 3D printing comes in. With Nike designers travelling to Kenya to get specific details of feedback from Kipchoge, the faster production technology was used to quickly take on board any suggested adjustments and get a new pair to him within 10 days. 3D printing also allowed Nike to replace the polyester Flyknit material with a lighter thermoplastic polyurethane material which reduced the shoe’s weight by six per cent.


The red underlay and green shimmer on the shoe symbolises the clay roads and organic greenery of Kipchoge's training in Kenya (Source: Nike)

“We found [with the original Vaporfly Elite] that by adding more propulsive materials underneath the foot we could offset some of the weight gain compared to a traditional racing flat,” says Schoolmeester.

Read more: Eliud Kipchoge's course-best time hailed as greatest run ever despite narrowly missing world record

“Yet we know that weight is the enemy of speed and efficiency. So one of the goals was: how can we pull weight off the shoe without sacrificing performance? We know for a fact that every 100g you take off the shoe, you gain one per cent in running economy. So every fraction thereof still helps.

“Knowing the midsole had already been finely tuned to find that balance, we looked straight to taking weight out of the upper.”

The final product that will be on Kipchoge and Farah’s feet on Sunday is 11 grams lighter than its predecessor. According to Schoolmeester’s formula, that equals a 0.1 per cent improvement in running economy.


Attention was moved to the upper part of the shoe in the pursuit of a lighter weight (Source: Nike)

“As far as those athletes are going, that’s a meaningful improvement,” he says.

For any London Marathon runners looking to make a last-minute boost to their times, a number of pairs of the shoes have been made available to buy this week, although they will have to fork out £499 to do so.

Yet Schoolmeester says it won’t be long before the 3D-printed technology used in these shoes will be prevalent in more affordable consumer products.

“It’s at a high price point right now because it’s a ‘concept car’,” he says.

“But it’s not going to be an unattainable price point when we bring it into other shoes. Because that is the future, bringing fly-print technology into other shoes in the training zone.”

That’s 0.1 per cent of the run done for you. You will still have to get off the couch for the other 99.9 per cent.

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