Deep inside Nike’s secretive scientific research laboratory, at its Portland headquarters, is one of its shortest pieces of running track. At 50 metres in length, the runway is long enough for runners to hit high speeds but it isn’t designed for breaking records.
It is, however, one of the most technologically sophisticated pieces of track in the world. At one end, stands Filip Ingebrigtsen, one of three brother’s belonging to Norway’s hugely successful running family. (Most of Norway’s middle distance running records – including 1,500m, the mile, 3,000m and 5,000m – are held by Filip, Henrik, and Jakob, who is just 18).
Stuck to each of Ingebritsen’s legs are 16 reflective sensors. As he accelerates down the runway hitting a pre-defined speed of 20kmph, 20 carefully positioned cameras around the air-conditioned room digitally map his every step.
When the runner reaches the middle of the track he lands on something different: a hard, sensor packed, metre-long pressure plate. The plate tracks which part of his foot – the fore, middle, or heel – hits the ground first, as well as the amount of energy the stride imparts into the ground and how this energy moves through his foot as he takes-off again.
It’s this technology which has in-part led to Nike’s latest shoe: the Joyride Run Flyknit. The shoe, which is being unveiled today, has been designed as a trainer that’s intended to help runners recover faster from their runs and at the same time try to minimise the impact caused by a person’s feet slamming into the ground thousands of times during a run. It’s claimed to be Nike’s most cushioned shoe.
Instead of an entirely chunky foam midsole, the company has inserted four cavities throughout its construction. These are filled with thousands of tiny Thermoplastic elastomers (TPE) beads, designed to provide shock absorption as each stride is made. Nike says it tested more than 150 different materials before settling on the plastic-rubber hybrid that makes up the beads.
Each time a runner’s foot hits the ground the beads are squashed down. The air around them is compressed meaning there’s more cushioning than if a standard foam was placed under a person’s foot. It works in a way that’s not too dissimilar to a sponge being squashed by a person’s knuckle.
But the company says getting the beads in the correct place, with the right density and making them useful to the running process was an intense process – one that its research lab and designers have been working on for more than five years. (The shoes are available to Nike members from July 25 and on general sale on August 15, priced at £159.95).
Nike’s teams say they started working on the shoe by trying to determine where bead-containing pods should sit. One of the first iterations had the shoe’s entire midsole acting as one cavity full of the plastic beads.
However, as is pretty predictable, all of the beads moved around as a person ran. “We use pressure maps, to put the cavities of beads where runners need them the most,” says Will Moroski, a product line manager at Nike. The four cavities are situated in the heel, under the foot’s arch, the forefoot and under the toes – more than 50 per cent of the beads are in the heel. “So within these cavities, the beans can migrate but they’re not allowed to migrate from heel to toe” he adds.
Nike isn’t the first to use beads though. Back in November 2017, Puma released its Jamming trainers which are filled with its NRGY beads. Puma’s version hasn’t adopted specific areas for the tiny filling, instead having the entire midsole of the shoe packed out with them. (Nike and Puma have also been involved in legal disputes about copying of technologies). The Joyride trainers also incorporate Nike’s softest foam SRO2 around the bead pouches. To keep them in place, each set of beads is wrapped in a plastic casing. To get to this point, Nike staff used pressure scanning data from thousands of runners – elite athletes such as the Ingebritsens, to people who run infrequently – to determine the best position for them.
To do this, the company has its pressure-laden track inside its research lab but also mobile testing methods. Portable pressure pads allow it to capture how people walk and the parts of their feet that hit the ground first. Plus there are more high-tech options: a treadmill that monitors foot pressure exists in the lab. “There’s an insole we can drop into the footwear,” one member of the research team says. “It’s basically the pressure platform on the go, and it’s between the foot and the cushioning.”
The end product is that each size of shoe is constructed differently, but the company hopes that they perform the same. In one single men’s size 9 shoe there are 11,000 of the tiny beads; a women’s size 6 has 9,000. The company experimented with beads, larger balls and also pellets during the creation of the shoe.
Kylee Barton, a senior director of running footwear at Nike, says alongside its manufacturing contractors it developed a new machine, which works like a cake frosting bag, to insert thousands of the beads into the cavities on the production line. This allows each pod to be filled to the exact percentage to produce the same level of cushioning – no matter the shoe size. “A woman’s size five and a men’s size 12 are getting the same experience, where if you think about some of our Air products today, that’s not always the case,” Barton says. Nike’s Air line of shoes uses sacks of air as cushioning but these are largely the same on all shoes and haven’t been customised for people’s different shoe sizes and potential weights.
The result – the company hopes – is a more personalised trainer than it has produced in large numbers before. This shoe-speak means that no matter what shoe size Joyride a person is running in, they’ll still get the intended effect of the cushioning beads. Each variation has been tweaked to allow the same level of softness. “It’s very difficult to personalise products at the scale we do,” Barton says. The company, like others in the industry, allows people to personalise their trainers in some ways – such as colour, and outer design – but these are largely aesthetic options. “It is honestly our most personalised product at scale.”
When you first put the Joyride trainers on, it’s impossible to miss the thousands of beads under your foot. The pouches are obvious on the sole of your foot but tend to flatten out as you run in them. Moroski adds: “For the very first time, these beads are responding personally to your stride.”
Both Moroski and Barton liken the effect of the beads as to walking on sand, but say instead of eventually hitting a dense compressed layer they respond to the forces that are being exerted. “The combination of the cushioning with that responsiveness, it allows your legs to not feel like they’re putting in as much work because it’s not as difficult to get back into that next stride,” Barton says. The staff don’t go as far as saying the shoes will help to prevent runners from getting injured – the claim would be almost impossible to back-up – but they suggest the shoe’s aim is to make running easier for anyone.
In Nike’s sports research lab, ahead of the launch of the cushioned shoes, the Ingebritsen brothers get special treatment. Their feet are scanned, prodded and poked in every direction to help create running shoes specific to their fast paces and techniques. The aim is to help them run more efficiently – and recover faster. “Our training is based on becoming fast, not on preventing injuries,” Henrik says. “The risk is always there, but without a risk there is no progression.”
But recovery is still important – the faster a runner can get back to training hard, the easier it will be for them to improve. And attempting to increase the amount of shock absorbtion a shoe can handle may decrease the chances of injury. Filip adds: “Injuries are always part of the game, and we have developed a system, where we can recover very quickly, be in good shape and ready to race as fast as possible.”
