If you're skeptical, chances are you're looking at Nike Vaporfly 4% shoes with a little suspicion. Sure, scientists have shown early on that these tricks can improve run-time by 4 percent, but researchers are putting 250-dollar shoes to the test in labs to find out how they can make runners more efficient and faster.
And Ever After the 4% of shoes made their debut for Nike's Breaking2 project, more and more runners are wondering if they're just meant to help runners like Eliud Kipchoge set world records, or whether they're setting the pace Average Joe can help for any kind of pace.
For all skeptics, take a look at what we already know about the biomechanics of Vaporfly 4% shoes, along with the latest answers to your most burning questions.
The Early Evidence
One of the first studies that considered the Vaporfly 4% was conducted in 201
However, one question remained: how do these shoes work in the real world with real runners? One of the more comprehensive analytical deep-sea dives was conducted by The New York Times in 2018. In their analysis, half a million marathon and half-marathon times were written after Strava (along with the shoes the runners wore)), reporters Kevin Quealy and Josh Katz confirmed the claim of 4 percent. In addition, runners of the same caliber were more likely to go for a PR that wore the vaporflys than other shoes.
"We've found that the difference is not explained by faster runners wearing the shoes, but by runners who wear them more easily, or by runners who switch to vaporflys after completing more training miles. Instead, the analysis suggests that a runner with vaporflys in a race between two marathon runners of the same ability has a real advantage over a competitor who does not wear them.
How do the Nike Vaporflys actually work?
The University of Colorado Boulder scientists, who had originally confirmed that Vaporfly's work worked as promised, followed a study in which examined the components of footwear – namely the carbon fiber plate and the Special ZoomX midsole foam runners actually save 4 percent of energy.
Late last year, published in Sports Medicine, This study involved 10 male runners, each working five minutes in three of the same shoes in her running study: Vaporfly, Zoom Streak, and Adios Boost. Using biomechanical 3D-Stride analysis and force plates, the researchers looked at how the runners' gaits (the way they moved their limbs) and the ground force reactions (how hard their feet touched the ground) differed between the shoes.
Based on previous studies, in which runners tended their knees less on particularly pliable (ie "muddy") treadmills than on normal treadmills, the researchers expected runners wearing vaporflys with a resilient foam to have their knees Knee bending would be less.
"Why this is important for energy is easy to imagine," said Wouter Hoogkamer, lead author of the study. told Runner & # 39; s World . "Get up now and stand with straight legs, try to get up and bend your knees 90 degrees. See how you think you can last longer. "
However, the runners' knee movement did not really differ between the three shoes.
Instead, Vaporfly's energy savings turn out to be three things: First, the ankle mechanics of the runners are improving, which is probably the curved carbon fiber plate From the heel to the toe, the researchers believe that the plate stabilizes your ankle in some way and reduces your "rotational power" – or the work that your calves normally need to do.
Secondly, runners lose less energy when the toe panel stays straight, because yes, your toes work and waste energy when you walk by bending over, and third, the ZoomX foam in the midsole has two unique features: an unusual one Level of compliance (he squeezes when landing your foot) and an unusual degree Resilience (it returns to its original shape and returns most of the energy your foot used when you landed). In fact, the shoe has an 80 percent energy recovery in the heel, which is the highest value we've ever measured in our shoe lab Runner's World .
Hoogkamer admitted that the average runner can not do much of the study. But it could help you to come up with an argument "that you should be absolutely legal" if you are for Vaporfly.
"There are many people who say that the plate [carbon fiber] acts as a spring. So if you have a strong opinion, then here are some additional data to consider, "he said. "Is it really the record that the game changer is or not? Not for me. It is the integration of the plate with the foam in this special area that works so well. "
Could the Nike Vaporflys hurt me?
One of the selling points of the Vaporfly is that they have more foam than most racing flats. The ZoomX midsole is so light. Theoretically, it seems that this would cushion a runner from the effects of the ground – which could reduce the risk of injury – but a study with extra padded or "maximum" shoes that were found differently.
Oregon State University -Cascades researchers compared the biomechanics of 15 female recreational athletes when wearing a neutral running shoe (New Balance 880) with a maximum running shoe (Hoka One One Bondi 4).
It is claimed that maximum shoes reduce shock when walking on the body as they are additionally dampened, reducing the likelihood of injuries such as plantar fasciitis and tibial stress fractures. The researchers therefore expected that runners would experience a lower vertical impact peak when wearing the maximum shoes – the highest force when the foot initially lands – and the load rate – how quickly you load force on your limbs as you move through your crotch , However, the researchers found the exact opposite true: both measurements were higher in the padded shoes.