Scientific study: Vaporfly 4% shoes provide 3% gains on uphills or downhills

How old is this study? The shoes tested are three or four years old.

Haven't read the article....but what % grade did they use?

Given most road marathon courses (i.e. Boston) that are "hilly" rarely hit over +/-5% grade a 2.8% improvement is still pretty good even on a slight incline or decline.

I mean this is pretty common sense: The force vectors change with a slope.

It's the same reason why carbon fiber plates and super foams aren't going to help much in mountain-ultra-trail races (given there are steep hills and rocky, uneven technical terrain). Maybe only on flat courses with fairly uniform surfaces that mimic roads they are helpful in ultras though.

For example see article I wrote here:

https://mutrunning.com/carbon-fiber-plated-shoes-on-trails/

The force that lifts your heel off the ground is your ankle lifting it up and forward around the planted forefoot. No bouncy sole has anything to do with this.

S. Canaday wrote:

Haven't read the article....but what % grade did they use?

Sage, big fan, but it pays off to read the article:

"The researchers tested two Nike marathon racing-shoe models, the Streak 6 and VaporFly 4%. 16 competitive male runners performed a series of six, five-minute trials (three in each shoe) on a downhill, flat and uphill grade (the downhill grades were moderate, at three per cent), and their submaximal oxygen uptake, carbon dioxide production and metabolic power were calculated for each test."

Study said +3% uphill, -3% downhill and 0% level. 6 x 5mins at each specified grade at 13kph (8.1 mph).

16 male athletes who had run sub 1:20 half or sub 35min 10k or equivalent in past year and lived in the area (altitude 1655m).

Seems slow speed for testing if the runners were used to racing at 10+mph (and some people have said the sweet spot for the carbon plated shoes is sub 7min per mile)

Lol, "only" 3%.

Before the VF, shoe companies were happy if they could get a 1% improvement in running economy on a flat course. 3% remains an amazing improvement

If you fall off a vertical cliff you will get literally 0% benefit. You literally will be a vapor fly if you jump off Thor Peak while wearing them.

They actually tested at 3 degrees incline/decline, which is about 5% grade...similar to Boston hills.

3 percent economy improvement on the hills is still very substantial.

https://www.sciencedirect.com/science/article/pii/S2095254621001113?via%3Dihub

Bad Wigins wrote:

The force that lifts your heel off the ground is your ankle lifting it up and forward around the planted forefoot. No bouncy sole has anything to do with this.

I just want a light comfortable shoe that dissipates less energy. It should be not too expensive and last a few races and tempo runs.

There are fast and slow shoes. And comfort levels vary a lot. Weight varies a lot. Durability varies a lot.

Not sure why they chose 13km/hour. An ~4% improvement on the flats means ~2s/minute. 2:00 every hour. 5:00 saved for someone running 2:30. That seems aggressive based on the 1-2 minutes that other studies have shown. Makes sense that someone running 7:30 pace for a marathon might get back more time. Guessing the gains would have been less at a faster pace. & shoes are one factor. You're running a test in a controlled environment. To get the full effects of the shoe, you need a perfect course, with perfect weather, & perfect pacing.

I'm still waiting for a study that looks at more variables, looks at all the shoes, and tries to find out how people respond to the shoes.

A 2 minute improvement in a 2.30 marathon would be huge.

But compared to what exactly? What shoes are being compared?

Nikey McShill wrote:

A 2 minute improvement in a 2.30 marathon would be huge.

But compared to what exactly? What shoes are being compared?

Compared to the Nike streak 6, an old style racing flat.

NERunner03533 wrote:

Not sure why they chose 13km/hour. An ~4% improvement on the flats means ~2s/minute. 2:00 every hour. 5:00 saved for someone running 2:30. That seems aggressive based on the 1-2 minutes that other studies have shown. Makes sense that someone running 7:30 pace for a marathon might get back more time. Guessing the gains would have been less at a faster pace. & shoes are one factor. You're running a test in a controlled environment. To get the full effects of the shoe, you need a perfect course, with perfect weather, & perfect pacing.

I'm still waiting for a study that looks at more variables, looks at all the shoes, and tries to find out how people respond to the shoes.

These are improvements in running economy not running pace. They’re measuring Oxygen consumption at one pace not seeing how much faster the test subject can run at a given oxygen consumption. The pace improvement between 2 runners with the same improvement in oxygen consumption might see different pace improvements.

These claims and studies backing them up have been around for 4-5 years now, why do so many people still not understand this?

Because they are very big claims that stretch credulity?

Measuring oxygen economy is easy. Explaining improvements is not.

These studies compare new shoes to older models. It would have been interesting to compare to barefoot shoe running. Shoes with a high stack height and a lot of foam will always dampen (energy is lost) more than shoes with less foam. Actually any foam will absorb energy that will be lost, at least any of today. New high-stack shoes have foam with less dampening effect and more spring-effect than older shoes. The leg and foot actually is built to do this job without a shoe, given it is strong enough.

The carbon plate does not offer dampening or spring effects, but it offers stability and probably a help for the foot to function with less effort over a longer time. Foot strength can also do this and this means that I think one should consider if always training with this technology in the long run is good, unless you do other strengthening workouts.

Now, I run as much as possible with barefoot shoes cause that gives me the best feedback and feel. I do not know if that is the most efficient shoes for me given the new technology. I believe I would never go to a high stack height, but I think a carbon plate in racing would have possibly helped me.

Are there any good studies on track shoes with carbon plates?

S. Canaday wrote:

Haven't read the article.....

<<a long paragraph later>>

For example see article I wrote here:

Do you see the irony here? Makes it obvious that you only come here to self promote.

Hi

I'm the senior author of the scientific article and I'd like to clarify a few things.

1. Is this a new study? Yeah, it was just published earlier this month. The data were collected in summer/fall 2019. The university shut down in 2020 which prevented us from collecting the biomechanics data as we had planned. The first author, Clarissa Whiting, started med school in 2020 and the middle author, Wouter Hoogkamer started a faculty position at U Mass Amherst in 2019. We held off publishing for a while, hoping that the lab would re-open. We decided to just publish what we had.

2. Grade: We chose 3 DEGREES (about a 5% grade) to approximate the hills of the Boston Marathon, the hilliest marathon major on roads.

3. Speed: We chose 13 km/hr because up a 3 degree hill, the rate of oxygen consumption at 13 km/hr is just about the same as 6:00 min/mile pace (16 km/hr) on level ground. So, about a 2:36 marathon pace.

To measure running economy, the subjects must be sub-maximal, i.e. ~ below lactate threshold.

It is feasible in Boulder to find a nice group of 2:36 marathoners. It is not easy to find a group of 2:20 marathoners who are willing to come to the lab.

Our previous studies (i.e. the first one from which the 4% got its name), studied level running at 14, 16 and 18 km/hr and the per cent savings were the same at the three speeds. In the present study, we wanted to study the effects of incline/decline, the level condition was just a sanity check and we found the same thing was we (and others) did in 2017, 18 etc.

4. Shoe choices: We already had the fresh Vaporfly 4% shoes and Streak 6s. The 4% savings have been replicated by several other studies and to my knowledge, nobody has yet published a study of the Next% or Alphafly shoes. There is one study hopefully forthcoming that compared 7 different shoes to the Alphafly and Nxt%2. That paper was discussed on these boards maybe 2 months ago. The Streak 6 shoes are a bit outdated, but we needed some shoes for comparison and since they were the de facto standard for the infamous 4%, it made sense to use them since our main question was whether the 4% would hold up or be exaggerated up or down hills. We could have used any shoes for a comparison. For examples we could have used a pair of classic Nike Cortez and maybe we'd find 12% savings. Our question was whether that would change to 11 or 13% up/down hills. Since Nike seems to make the same Nike Cortez shoes every year, I do recommend that they would be a nice "gold standard" to use in future studies. Any other model we choose will become extinct in a year or two.

5. Yes, as we note in the paper, studying steeper inclines/declines would be interesting and more relevant for trail running/racing. Science is incremental.

6. Are we shills for Nike? Nike pays me very modestly as a consultant and they have supported our research in the past. This study received no separate funding from Nike. Clarissa Whiting has no Nike affiliation. Wouter Hoogkamer has been supported by Nike in the past when he was my post-doc, he has done and is doing research supported by Saucony and Puma in his own lab. Some folks accused us of being shills in 2017 and our findings have been since confirmed by at least 4 other independent labs since then.

7. We and just about everybody else we ask/asked (Geoff Burns, Alex Hutchinson...) have/had hunches about how the results would come out. Most predictions were wrong. Intuition is fine, but experiments are how we gain knowledge. Everything is clear and obvious in hindsight.

OK, time to put on my Nomex suit.

rk

Rodger Kram, Ph.D.

Associate Professor, Emeritus

Integrative Physiology Dept.

University of Colorado Boulder

I actually don't see the "irony". I mainly wanted to illustrate that thumbnail image that displays with some creatively drawn arrows and "force vectors" to demonstrate the idea of changing slopes.... I had already assumed the % grade was 5% or less. Turns out I didn't need to read the article as it was just under that value. Makes sense with the parameters Rodger et. al chose as well (velocity etc). I assumed it was geared for hilly marathon courses like Boston (and not mountain ultras) and for fairly fast runners. Of course Running Economy % improvements don't necessarily translate to an exact drop in running pace improvements....however for most people there's going to be a very, very strong correlation. Another example of strong correlations like this (although in the opposite direction with a "slow down effect") would be the concept that Vo2max might (on average) drop by 10% going from sea level to 7,000' of a lot of runners, but average Running Economy does not drop by as much in terms of % value because of the benefits of lower air pressure (less air resistance) negate some of that loss and therefore Velocity at Vo2max does not drop as much. Still there is a very, very strong correlation though (of a drop in Running Economy and a drop in Vo2max and how that changes pace). It is likewise true for Running Economy improvements and improvements in actual race pace.

holterskolter2 wrote:

S. Canaday wrote:

Haven't read the article.....

<<a long paragraph later>>

For example see article I wrote here:

Do you see the irony here? Makes it obvious that you only come here to self promote.