The Tokyo games are finally set to go. Before they were first postponed, I looked into the technology behind the all-conquering Nike Vaporfly – and whether it amounted to “technological doping”
Martyn Rooney can remember the first time he truly felt the power of his shoes. The 400m Olympic sprinter was deep into his training for the 2016 European Championships, at a small race meeting in Holland. “I put these new spikes on, drove out the blocks and had never moved like that before,” he recalls. “The way I was covering the ground, it was just different.”
The shoes were Nike Zoom Superfly Elites. Rooney is 6ft 6in, so his were size 13s – it meant he had to wait longer than most, smaller-sized athletes for his pair. Frustrated, he laced them up for the race having not even worn them in training. “They were so much lighter than anything I’d worn before: like slippers with grip,” Rooney says. Not used to wielding their power, his brand new kicks catapulted him forward. “I went flying through the first 200m. It was at PB pace easily, probably the fastest I’d ever gone before in any race or training. I was too fast – I died horribly on the home straight.”
Rooney’s legs couldn’t keep up with his shoes. But he swiftly learned how to harness their speedy potential: he won gold at the Europeans a month later, lined up in Team GB’s 4x400m relay team at the Rio Olympics, then won bronze at the 2017 World Championships in London. Most would call that innovation in sport, where new technology helps drive the athlete further, push boundaries and achieve greatness.
But a recent shoe ruling from the sport’s governing body, World Athletics, has clamped down on footwear that gives athletes a supposed unfair advantage. It came following one mad marathon weekend in October 2019. First, the greatest marathon runner of all time, Eliud Kipchoge, made history by breaking the two-hour barrier. The next day, Brigid Kosgei smashed Paula Radcliffe’s 16-year-old women’s marathon record. The common denominator, besides being both Kenyan and superhuman? They were wearing versions of Nike’s Vaporfly Next% shoe.
Although Kipchoge’s run doesn’t appear in the record books (it wasn’t an official race and he was assisted by fresh pacemakers throughout), Kosgei’s definitely counts. It rubber-stamped a record-breaking year for distance running – and for the Vaporfly. It now lays claim to the five fastest official marathon times in history. At the Valencia Marathon, an estimated 95 of the top 100 finishers were wearing the shoes. Since its debut version in 2016, twice as many men have run under 2:10 and twice as many women have run under 2:27. World Athletics has since been forced to set tougher qualification times for the Olympics marathon – should it go ahead – in order to avoid too many runners on the starting line.
All the top ten male finishers at the 2019 Chicago Marathon wore a pair of Vaporflys. American Jake Riley was one of them – he said the trainers were like “running on trampolines.” A group of Adidas athletes, meanwhile, complained that the shoes were “ruining the sport,” claiming that they were allowing elite athletes to run two minutes quicker in a marathon. Others have gone further, likening it to “technological doping.” The running snoop Instagram account, @protosofthegram has clocked athletes from other brands running in blacked-out Vaporflys to get the benefit of the shoe without losing their regular endorsement.
Nike’s Vaporfly Next% shoe, launched in 2019, was worn by the record-breaking Kosgei at that year’s Chicago Marathon. PASSKHONPHOTO/SHUTTERSTOCK.COM
Enter World Athletics. Its new ruling limits shoes to a 40mm sole height for the road and 30mm for the track; one carbon-fibre plate (responsible for giving athletes a ‘bounce’ effect when they run); and bans prototypes in officially sanctioned races. The Vaporfly and the Alphafly, in theory at least, were both ruled legal.
For some in the footwear business, however, the complaints against Nike are just sour grapes. “It’s purely innovation, 100 per cent,” claims biomechanics expert Simon Bartold, a former international consultant for Japanese-based brand Asics. “Some are getting a bit hysterical, claiming that it’s ‘EPO for shoes.’ Nike has had this product visible for years, so people know what it is. I know how this process works – and it’s bloody hard work. There’s nothing stopping the other companies from getting in the lab, doing the hard work, getting the materials and construction right, and spending the money.”
“What makes these shoes so powerful? nobody has a clue”
Bartold, now director of footwear for Australian company XBlades, is also worried the clampdown could stifle creativity – especially when it comes to prototypes. When Kipchoge broke the two-hour mark he was wearing a reworked prototype version of the Vaporfly: the Air Zoom Alphafly Next%. “Prototypes make the world go round,” Bartold says. “The technology that goes into F1 cars percolates into family vehicles. It’s the same with running shoes – there would be benefits that would trickle down to weekend warriors and novice runners.”
Among those weekend warriors is Anne Chinoy of Manchester-based Sale Harriers. She says the Vaporfly has definitely boosted her performance, and countless others at the running club, since she first laced them in November 2019. “I immediately felt the benefit. I was running faster and no longer feeling shin pain. My clubmates have said my running style has changed: my knees are coming up more, my stride is quicker and stronger. I did a 10k three weeks ago and got my fastest time in two years. With a kilometre to go I’m normally hanging on, but I was just bouncing on to the finish line.”
Nike claimed that the Vaporfly’s combination of energy-returning foam and its “built-in secret weapon” – a carbon-fibre plate – made it four per cent more efficient than any other shoe. But it was more than a marketing gimmick: studies have shown that the average return for athletes is more than four per cent. Bartold says it can vary as high as six per cent. Over a marathon distance, that’s huge.
Kosgei pictured at the 2019 London Marathon, wearing a pair of you-know-what. DAVID SMITH 1965/SHUTTERSTOCK.COM
So, what makes these shoes so powerful? “The answer is nobody has a clue,” Bartold says. In Nike’s Beaverton, Oregon HQ, researchers would have spent years in the lab experimenting with footwear ingredients, concocting the perfect shoe formula, throwing in elements like geometry, foam composition and construction method into the mix. “I suspect they lucked upon the right combination and it came together in a perfect storm,” adds Bartold. “They now have the magic formula.”
The best we can do is guess. Bartold muses that it’s the foam that’s having the greater effect on times, rather than the lever-like carbon-fibre plate. He compares it to a sound wave hitting a soundproof wall. “I think the Vaporfly is doing the same thing: because of the foam, the geometry and the construction; it’s reducing the input vibration, which means you don’t have to contract your muscles to the same degree.” The result over 26.2 miles? Kipchoge runs in record time and looks fresh enough that he could repeat the trick.
From World Championships down to Saturday morning Parkruns, look down at any starting line and there is now a sea of neon pink and green flyknit. Chinoy says that one 50-year-old Sale runner has scored PB times at every distance since he donned Vaporflys, and that his legs now never tire. If those kinds of results were packaged up and sold over the counter in pill form, it would undoubtedly be deemed illegal. So, why not shoes? “I definitely sympathise with the view that people are nicking minutes off their time and it’s only down to their shoes,” Chinoy says. “But it seems curious that you wouldn’t want to develop and innovate the sport.”
Unlike most PEDs, wearing a pair of Vaporflys won’t harm an athlete’s long-term health. In fact, according to Chinoy, they help protect her joints and reduce fatigue – aiding correct running form, reducing the risk of injury. They’re also available for all, for a cool £209.95. Sure, if you’re not running in them, you’re pretty much at a disadvantage. But in athletics, that’s nothing new.
Look out for aqua flyknit at your next starting line – the Next% 2 were released in 2021. QWRET/SHUTTERSTOCK.COM
From the genetic lottery to multimillion dollar training camps, there’s no real level playing field in sport, let alone athletics. Andy Brown, editor of The Sports Integrity Initiative, compares the Malawian Sport Council’s 2017 budget to that of British Cycling’s for the 2016 games. “The first is £1.8m, the other more than £30m,” he says. “Likewise, someone will always have a natural physiological advantage over another. Sport needs to stop talking about a level playing field: the playing field is invariably never level.”
Brown also points to the sport’s inconsistencies, and the governing body’s insistence that Olympic Gold medallist Caster Semenya has to take testosterone suppressants in order to race in certain events. “World Athletics is saying that a potential six per cent advantage is OK to have from a shoe. Yet, at the same time, there’s a clampdown on the level of endogenous (naturally occurring) testosterone in certain women’s events – which is definitely less than two per cent. Why is one acceptable, and one isn’t? I find it a bit disingenuous.”
“The bottom line is that there isn’t, and never has been, a level playing ground”
Given the non-existence of the level playing field and sport’s general inconsistencies, should World Athletics have waded in with its ruling in the first place? Rooney thinks so. “It’s more about putting a limit on things.” He references Nike’s new (and illegal) Viperfly spikes, which utilise carbon-fibre plates as a spring mechanism. “Once you get to the point that guys are literally bouncing down the track, they’re 5’10 and have the stride of a 6’6 athlete, that’s a bit of a joke.”
But it’s going to be hard to police. Unlike when Fina, swimming’s governing body, banned the Speedo bodysuits that had resulted in 130 world records tumbling, examining what’s inside of a shoe is trickier. “Short of demanding athletes to take their shoes off and sawing them in half, there’s no way of telling if they’re a prototype or not,” argues Bartold. “They’re relying on an enormous amount of good faith which, when it comes to high-end athletic competition, goes out the window a bit.”
The likes of Adidas, New Balance and Under Armour will now be throwing hundreds of millions of dollars into research and development, in a footwear arms race to catch up with Nike. The World Athletics ruling, however, has the danger of stymieing innovation – maintaining a status quo with Nike miles ahead of the chasing pack. Bartold says that the biggest sport brands work in the future – they’ll be working on shoes for the Paris 2024 games that will make the groundbreaking Alphafly obsolete.
When the Olympics do finally go ahead, and athletes finally make their way to the starting line, what is certain is that it will be a very different sporting world. “There do need to be limitations, rules and regulations,” Bartold says. "Nobody wants to see a company coming out with true mechanical devices. But Nike has created a whole new genre of footwear that is well within the rules. The athlete still has to be strong enough to exploit the shoe. The bottom line is that there isn’t, and never has been, a level playing ground.”