Over the past four months, the running world has been enraptured by two competing efforts to break the storied two-hour barrier in the marathon.
Nike set the tone first, announcing its effort, dubbed Breaking2, in December. Not to be outdone, the Swoosh’s chief rival, Adidas, struck back in March with its Sub2 program and its adizero Sub2 marathon training shoe.
The Sub2 debuted at the Tokyo Marathon Feb. 26 by elite marathoner Wilson Kipsang, who ran just 61 seconds slower than the world record of 2:02:57, set in 2014 by Dennis Kimmeto. A little more than a week later, Nike unveiled its competing shoe, the Vaporfly Elite, which three world-class runners will wear in the company’s own sub-two-hour attempt: Rio gold medalist Eliud Kipchoge (PR 2:03:05), Boston Marathon winner Lelisa Desisa (PR 2:04:45), and Zersenay Tadese (world record of 58:23 in the half-marathon).
Sure, it’s brilliant competitive marketing. And there’s no denying that a clash of two titanic brands could yield some notable breakthroughs in the cutthroat world of running shoe technology.
But the question remains: If these shoes are designed for the gods of distance running, will they do anything for mere mortals?
First, one thing needs to be clear: Joe Marathoner won’t even be able to buy Nike’s Vaporfly Elites—which are custom-made with a curved carbon-fiber plate specially adjusted for each runner privileged enough to wear them—much less run in them.
For his off-the-shelf model, Joe will need to wait until June 8, when the Vaporfly 4% shoe is released.
The “4%” moniker applies to Nike’s estimate of a 4% gain in efficiency, the result of a major technical advance in the form of super-lightweight foams designed to put more energy in a runner’s step. Nike’s ZoomX foam cuts a size-10 pair of Vaporfly 4% shoes down to a mere 6.5 ounces. Adidas’ press release doesn’t say how much weight the Boost Light foam reduces from the Sub2s, but the company notes that a reduction of 100 grams (3.5 ounces) can translate to a 1% gain in running economy.
(For the sake of comparison, a typical running trainer like Nike’s Air Zoom Pegasus 33 weighs 10.8 ounces, or 306 grams.)
But here’s the thing: A 1% speed increase could be hugely helpful for the best runners in the world—obviously, shaving two minutes off a marathon time could make all the difference in a sub-two-hour attempt. But will it make a difference for people with anything but biomechanically perfect form?
Possibly, says podiatrist Nick Campitelli, D.P.M., author of the popular Dr. Nick’s Running Blog, since—especially if you’re a very competitive runner—the 1% speed increase offered by the adizero Sub2 or the Vaporfly could gain you a slight competitive edge.
However, wearing this type of ultra-fast shoe for training—as opposed to racing only—could actually hurt your times more than help them, Campitelli says. “You don’t need fatigue on the day you’re trying to do your best, but at some point you do,” he says.
Campitelli conducted a study that showed that minimalist shoes, because of their lack of padding and negligible structure, actually helped foot muscle develop. So, he speculates, “if you reduce fatigue in every run”—which ultra-high-tech, energy-restoring foams might do—“then the average runner wouldn’t be stressing the body or the foot to adapt, and they’d eventually become weak.”
There’s another big reason to wonder if the shoes’ appeal will extend beyond elite marathoners and the small group of runners who are always pursuing the latest shoe technologies: How much it will cost runners to get their hands on a pair?
Take Nike’s Vaporfly 4%. The name may refer to not just the efficiency gain the shoes may offer, but the upper 4% income class who’ll be able to afford their $250 price tag.
That price alone could deter many runners, says Jean Knaack, executive director of the Road Runners Club of America. “I don’t foresee the masses buying the shoe in large numbers,” Knaack tells Men’s Fitness. “There’s an audience that will buy a trend because it’s new. But longterm, I think people will stick with the more traditional running shoe that’s currently on the market.” (Men’s Fitness reached out to Nike for comment, but as of publication, no representatives had responded.)
Campitelli agrees. “There’s a select population of people that will buy this,” he says. “We see gimmicks and pendulum swings all the time in regard to shoes, and I feel this will be one of those. It may be good for elite racing, and runners attempting [to break the two-hour mark], but I don’t know that it will find its place in helping everyday runners.”