Titanium, carbon-fibre, 3D printing and wind tunnels all contributed to making the lightest and fastest race day kit.
By Jeff Dengate
We’re just two weeks away from Faith Kipyegon’s attempt to become the first woman to run faster than 4 minutes in the mile. (A mile is 1.6 kilometres. To run that distance in 4 minutes, Faith will have to run a 2:29 kilometre pace.) Now, we’re getting a first look at the cutting-edge shoes and apparel she’ll wear during the event.
I recently visited the Nike Sport Research Lab in Beaverton, Oregon, for an up-close look at the gear and to speak with the team that created it.
Nike product developers often use the phrase, ‘right weight, not lightweight’ in explaining how they balance product performance and durability concerns. But when it came to Kipyegon’s custom equipment, every single gram was scrutinised.
Nike didn’t have to sacrifice lightness to maintain durability. After all, Kipyegon really only needs the pieces to last for four laps of the track— a far different requirement than an amateur track athlete who has one pair of spikes and needs them to last through a full outdoor season of training and racing.
‘The team did an amazing job completely reimagining and really thinking through the trade-offs and benefits, like, what do we keep that adds performance?’ said Carrie Dimoff, program director of footwear innovation. ’What can we get rid of that was adding weight?’
Victory Elite FK Track Spikes
Footwear advancements have helped to rewrite the record books on the track, with high-tech foams and lightweight carbon-fibre plates unlocking new achievements. Kipyegon’s go-to racing shoe has long been the Victory 2. But when Nike set out to specifically optimise a shoe for her alone, designers saw an opportunity to dramatically cut weight to make an even faster platform.
The result is the Nike Victory Elite FK. The name is a nod to Faith Kipyegon, but also ‘fastest known’ [time].
Jeff Dengate
The Victory Elite FK has a carbon-fibre outsole plate and six titanium pins to maximise weight savings.
During my product briefing, Dimoff said the team went through many iterations, and even took all the necessary equipment to Kenya so designers could make alterations on site based on Kipyegon’s real-time feedback. In the end, Nike has come up with a shoe that weighs just 85g, and is 25% lighter than the Victory 2 she had been wearing to race.
Jeff Dengate
Let’s look few key innovations:
A taller Air unit delivers even greater energy return.
More Air: Yes, modern foams have greatly increased cushioning and energy return, all at lighter weights. But Nike’s gold standard remains its Air units. No foam delivers the same amount of energy return, so Nike looked to push that tech even further. The result? The tallest Air unit ever built into a track spike.
Insanely lightweight upper: The FlyKnit upper material is astonishingly light at just 3g, Dimoff said. To put that into perspective, she told me it’s the same weight as just three paper clips. Because Nike didn’t have to worry about durability or the prohibitive costs of commercialisation, they were able to look at yarns they previously couldn’t use in shoes.
Jeff Dengate
Nike used a new lightweight yarn it’s never before used in a shoe.
‘We also adjusted the knit structure,’ Dimoff said. ‘This is a more open structure than we’ve used on some of our other shoes to emphasise that lightweight. Is this strong enough for someone to run a hundred miles in? We don’t know yet. But when we look just through the lens of one mile, (1.6KM) certainly we kind of change the way of thinking.’
Titanium pins and carbon sole: Most track spikes incorporate a rigid plastic sole and metal pins. But, again, Nike looked to some of the lightest and strongest materials. The outsole looks impossibly thin. I didn’t bust out my callipers to measure it, but in my recollection it can’t be much thicker than about five post-it notes.
‘It’s really just there for holding in the traction pins,’ Dimoff explained, saying that any traction elements like triangles or ridges were removed for the same reason. ‘The primary function of that is to be rigid enough to create stability and tie the system together, but mostly to hold those traction pins. Other materials [plastics] probably couldn’t handle being that thin and still be structurally strong.’
This prototype began with just four pins, like the Victory, but Nike knew the shoes needed at least one more for additional grip. In testing, Kipyegon asked for yet one more after testing a semi-finalised version. When hitting mile pace, she felt like she needed a little extra grip at toe off, but said she wasn’t entirely sure. ‘She was like, “maybe the track is wet today,”’ Dimoff recalled. So, Nike left her with pairs in both configurations to test out, and the six-pin version proved to be the winner and gave her the slight extra confidence.
Is it World Athletics legal? Technically, no — but not because of the reasons you may suspect. According to Dimoff, the shoe’s stack height is actually within the permitted limits (under 20mm thick), even with the taller air unit. But Nike isn’t submitting the shoe for approval, a process that can take considerable amounts of time. Instead, they’re preserving that time in case they need to tweak. Dimoff told me they have to freeze the design at some point, but could be making adjustments up until about a week before the event.
Courtesy of Nike
Nike crafted a custom speed suit for Faith Kipyegon’s attempt at a sub-4 minute mile.
Fly Suit
Nike has famously made edgy racing kits in the past. At the 2000 Summer Olympics in Sydney, the winner of the 400 meters, Australian Cathy Freeman, wore a hooded, full-length, green-and-gold speed suit that looked straight out of a comic book. Ahead of the 2016 Summer Olympics in Rio, Nike rolled out team uniforms with small shark fin-like blades affixed to singlets, calf sleeves, and even fabric tape, which the company said could shave a ‘fraction of a second from sprinters’ times’.
Kipyegon’s ‘Fly Suit’ is more akin to the 2016 uniforms, but built with the same focus: reduce as much air resistance and drag as possible.
The main part of the suit is one-piece and sleeveless, made from a slick and stretchy fabric, and the bottom will cover most of Kipyegon’s thighs. Arm and leg sleeves, plus a headband, complement the look. All are covered with strategically placed ‘Aeronodes’.
Nike tested the node placement in a wind tunnel and optimised it to help air flow smoothly around Kipyegon’s body and leave smaller eddies in her wake. That testing led to an interesting detail that Nike shared about its obsessive drive to minimise energy loss. The nodes on the side were spread out on both sides of a seam. But they found that such a break up of the nodes design wasn’t optimal, so the designers shifted the seam further on Kipyegon’s back and brought the nodes together, leading to less wind disruption.
Courtesy of Nike
Half-dome shaped bumps called Aeronodes are strategically placed to improve aerodynamics.
Like it did with the shoes, Nike sweated every detail of the Fly Suit and created many versions — including modifications in Kenya during testing with Kipyegon. The team would watch to see if Kipyegon was tugging at the legs or adjusting a shoulder strap, which could be subconscious feedback that the fit wasn’t dialled quite so perfectly.
‘One of the other things that we were looking for, as well, with the arm sleeves was “is she pulling them up?”’ Lisa Gibson, expert product manager of apparel innovation, told me in Beaverton.
‘On some of her track workouts, when Faith would have a moment where maybe she’s doing a 400 and then taking a moment, if she was adjusting that during the rest period we knew it’s not staying up where it needs to be, maybe it’s drifting down a little bit. So those are the moments that we’re looking for.’
Courtesy of Nike
Faith Kipyegon’s sports bra is 3D printed.
FlyWeb Bra
Remember those jelly shoes from the 1980s? That’s what I immediately thought of when I saw the 3D printed sports bra that Kipyegon will wear for the attempt. The FlyWeb Bra uses a TPU material to make it as lightweight and breathable as possible, but also to remain soft.
TPU is a polymer that can be turned into a foam — it’s used in some running shoe midsoles, most famously the Adidas Boost line — but in this case, it forms a rubbery spider web that turns into a racerback bra. And since the material is hydrophobic, it won’t absorb any sweat as Kipyegon races. It also delivers the distraction-free support she needs for race day.
‘Because we’ve leveraged computational design, this entire structure is really thoughtfully engineered and that allows it to provide tuned support,’ Gibson said.
Like the other pieces of gear, this was custom-built specifically for Kipyegon, but elements of it may eventually make their way to consumer products in the future. Gibson told me Nike feels like this is going to help a lot of athletes.
And it’s not just a product reserved for four-minute speed. ‘The ultimate stamp of approval for us is the fact that we left it behind, we gave her the option, and she chose to wear it and train in it,’ Gibson told me. ‘The product is working. She loves it.’
When can you see it in action?
We’ll see just how much all of this gear helps Kipyegon in her attempt when she toes the starting line at Stade Charléty in Paris on June 26.
The event will be streamed live on Nike’s YouTube, Instagram, TikTok, and Douyin accounts as well as on Prime Video at 3:15am AEST June 27 (7:15 p.m. CEST June 26). A replay will be available shortly after the attempt.
From: Runner’s World US
