When running in the Vaporfly, the runners had a lower cadence and longer strides, and a greater peak force against the ground. So the benefits don’t accrue only to fleet midfoot-striking elites.įinally, they looked at various biomechanical parameters to look for clues about how the shoes worked. The heel strikers got a slightly bigger advantage (4.63 percent better than the Boost) compared to the midfoot/forefoot strikers (3.50 percent better than the Boost). Here’s what the individual running economy looked like for the three speeds (NS is the Streak, AB is the Boost, and NP is the Vaporfly prototype):Īnother key detail: 8 of the subjects were heel strikers, and ten were midfoot or forefoot strikers-not that it ended up mattering much. What about individuals? Remarkably, every single runner in the study was more efficient in the Vaporfly than in either of the other two shoes. And this is despite the fact that they added 51 grams of lead pellets to the Vaporfly to make them the same weight as the Boost shoes.īut average results are just part of the story. In 18 sub-elite runners, the amount of oxygen consumed (which is a proxy for how much energy you’re burning) was lower by an average of just over 4 percent in the Vaporfly compared to both other shoes, at three different speeds between 6:54 and 5:22 per mile. The headline result, of course, was the change in running economy. ![]() Outsourcing some of this shock-absorption to the shoes may save a bit of energy that you’d otherwise spend contracting the muscles around your knee joint. In hard shoes on a hard surface, you bend your knees more to absorb the impact in super-soft shoes, you keep them straighter. When you run, you naturally adapt your stride to get the “right” amount of shock absorption. This off-the-charts compliance could be one of the shoe’s key advantages. There’s something going on with these shoes. This is what you get from having the Vaporfly’s distinctively huge platform of foam under the shoe’s heel.īut these are rigorous results from a respected laboratory. The other aspect of the mechanical testing was compliance: How much does the shoe squish down when you press it? In this case, the Vaporfly was almost twice as compliant as the other shoes, deforming by 11.9 millimeters compared 6.1 for the Streak and 5.9 for the Boost. The authors note that versions of these two shoes (the Streak 6 and the Boost 2) had been used for all ten of the fastest marathons in history at the time the study started, in April 2016. It returned 75.9 percent of the input energy. Interestingly, they also tested the Adidas Adizero Adios Boost 2, which was used by Dennis Kimetto to set the current men’s marathon record of 2:02:57. The Vaporfly prototype they tested returned 87.0 percent of the energy, compared to just 65.5 percent from Nike’s previous state-of-the-art marathon racer, the Zoom Streak 6. Still, they did some basic mechanical testing, slamming a force actuator into the shoe and measuring the recoil to see how much energy it returned. Importantly, the Colorado study didn’t aim to figure out how the shoe worked it was only designed to assess how well it worked. ![]() The general outlines of the study were presented earlier this year at the American College of Sports Medicine conference (I wrote about them here), but there are some intriguing new details that are worth exploring.Īt the heart of the shoe is a foam sandwich, with thick layers of a new foam surrounding a stiffened carbon-fiber plate. On Thursday, the journal Sports Medicine finally published the complete peer-reviewed data behind the four percent claim (the full text is freely available), from a team at the University of Colorado’s Locomotion Laboratory led by Rodger Kram and his post-doctoral research associate Wouter Hoogkamer. Nike hoped the shoes would help Kipchoge break the two-hour barrier-and although he didn’t quite make it, his performance launched a debate about the shoes that’s still going on. The “4%” label refers to the claimed improvement in running economy, a measure of oxygen consumption at a given pace, compared to other state-of-the-art marathon shoes. The Vaporfly shoes made their official debut in the lead-up to Nike’s Breaking2 marathon in Monza, Italy, in May, where Eliud Kipchoge notched a mind-blowing 2:00:25, albeit under non-record-eligible conditions thanks to a rotating cast of pacers blocking the wind for him. A four percent boost, as the name of the shoe promises? That’s child’s play: Herron’s time of 12:42:39 sliced more than an hour-and 8 percent-off the previous mark. But earlier this week, Nike’s controversial Vaporfly 4% shoes tagged along for their first world-record ride, when Oklahoma-based ultra star Camille Herron shattered the 100-mile mark at the Tunnel Hill trail race in Illinois. ![]() Admittedly, it’s not the record they were originally planning for.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |