“If a running shoe made you 25 percent faster, would it be fair to wear it in a race? What about 10 percent? Or 2 percent? The Nike Zoom Vaporfly 4% — a bouncy, expensive shoe released to the public one year ago — raises these questions like no shoe in recent distance running history.”
"Using public race reports and shoe records from Strava, a fitness app that calls itself the social network for athletes, The Times found that runners in Vaporflys ran 3 to 4 percent faster than similar runners wearing other shoes, and more than 1 percent faster than the next-fastest racing shoe.
We found that the difference was not explained by faster runners choosing to wear the shoes, by runners choosing to wear them in easier races or by runners switching to Vaporflys after running more training miles. Instead, the analysis suggests that, in a race between two marathoners of the same ability, a runner wearing Vaporflys would have a real advantage over a competitor not wearing them."
After reading all the reports and seeing that a lot of pro triathletes had started wearing them I was very curious. At IM Cairns just over a month ago now I saw pro Luke McKenzie registering wearing a pair and had met him in Kona last year so I bailed him up to ask what it was about the Vaporfly 4%. He said they are well cushioned and just seem to give more energy back with him running faster in them. I am sure a lot of people out there have run in them but I had been balking at spending that much on a shoe to that point. Now I just want to know where I can buy a pair without having to pay $500 off eBay. See the other interesting thread running about the difference between Hoka Clifton and the Zoom Fly. Seems other shoes are adding a carbon plate and using the same rubber including Hoka so hopefully we will get alternatives at a cheaper price and accessible soon enough???
While I would love to see a well-controlled double-blind study, I have to be happy with someone at least doing some level of testing. It looks like the big winner out of this is the Nike Streak because of its performance and general availability. I still haven’t been able to get my hands on a pair of Vaporfly 4%. I am sure I could have scoped out eBay but I am just not willing to pay those prices. I did try the Zoom Fly (non 4%) and it was my least favorite shoe of all time.
I also found the IAAF rules and reg interesting. I assumed there might be something in there but good to know…
The rules also state that shoes “must be reasonably available to all in the spirit of the universality of athletics."
Fwiw, the Nike Streak was the second shoe, which was still 1% faster than the third shoe and only 1% off the Zoom Vaporfly and is half the price and readily available. Seems like a worthy substitute, and given that IMHO the average Zoom Vaporfly person is looking for a PR and probably is extra motivated, that probably adds to any over-performances in the shoe. It would be interesting to control for mileage as well given the relatively short life of the Vaporfly.
From reading reports the Streak doesn’t have the same cushioning as the Vaporfly and I wouldn’t be doing an Ironman in a set like I would consider the Vaporfly. I still want a pair to satisfy my curiosity but hate the fact what Nike is doing giving limited supply to jack the price. I generally run in Hoka so hoping they release a reported carbon plate version soon as I am sure it will be readily available.
It really seems everyone is confusing what Nike are claiming with their shoe. They are claiming that the shoes are 4% more effective, not that you will run 4% faster.
Would like to try them out, but haven’t got a hold of any and I’m guessing they won’t restock until the new flyknit are out.
That’s what Nike are claiming, but the analysis that the article is referring to also found them to be 3-4% based on Strava data. I’m still pretty sceptical as to how you control the data set to get a clean result when there are so many factors in, but interesting nonetheless. It does seem to me that on an expensive shoe with a short life then people will wear it more for races or fast training sessions, I’m sure they thought of that but don’t know how you eliminate it. Unless you control for HR and course - e.g. Athlete A runs 3-4% faster in his Nikes than his Brand Z shoes, on the same routes and at the same HR.
Well the article shows them as 1% faster than other fast shoes, so it could also be quite likely that many people were used to wearing heavier shoes and got a boost from wearing lightweight shoes. I know of at least one person who switched from Mizuno Wave Runners to 4% for his latest marathon, which is a huge difference, but he would also have had a huge improvement if he went with adios, boston or some of the other fast shoes.
Also as you said, controlling for this study is very hard.
I think its cool how this data can actually help to validate market claims. And while personally this is certainly not rock solid data in my book this is a pretty nice start.
On the other hand I would not consider these regardless of whether theres 0.5 or 5% gain to be had until they’re at least readily available for mere mortals. Theres a limit as to how far I will let myself get ripped off by companies, and if Nike is artificially creating shortage of these to feed hype and inflate prices I’m pretty sure I can do with Hokas for another couple of years. Good for Nike they’re driving innovation but in a world where $1500 pulley wheels exist I feel like we’re being tested as to how stupid we really are and must reconsider how far we’ll let this go.
“If a running shoe made you 25 percent faster, would it be fair to wear it in a race? What about 10 percent? Or 2 percent? The Nike Zoom Vaporfly 4% — a bouncy, expensive shoe released to the public one year ago — raises these questions like no shoe in recent distance running history.”
"Using public race reports and shoe records from Strava, a fitness app that calls itself the social network for athletes, The Times found that runners in Vaporflys ran 3 to 4 percent faster than similar runners wearing other shoes, and more than 1 percent faster than the next-fastest racing shoe.
We found that the difference was not explained by faster runners choosing to wear the shoes, by runners choosing to wear them in easier races or by runners switching to Vaporflys after running more training miles. Instead, the analysis suggests that, in a race between two marathoners of the same ability, a runner wearing Vaporflys would have a real advantage over a competitor not wearing them."
I’m not sure of the point you are trying to make? Aero kit is faster than flappy kit, aero TT bike is faster than sit up and beg bike. Nike shoes faster than converse… etc.
I’m not sure of the point you are trying to make? Aero kit is faster than flappy kit, aero TT bike is faster than sit up and beg bike. Nike shoes faster than converse… etc.
to be a bit controversial nike’s fast shoer miles faster than hoka’s fast shoes would be the point he is making
Another thing to note is if these shoes were in fact 4% faster than any other shoe, we would see pros running sub 2. These shoes are maybe faster than other racing flats by a small margin, and are a lot faster compared to the average runners shoes, but if you are already wearing lightweight shoes you will likely only notice a small difference. There is a rough estimate of how running speed is affected by shoe weight, one sec per mile faster for each ounce lost. If you compare the vaporflys which weigh 6,9 ounces to Mizuno Wave rider which is over 10 ounces which means the savings are around 6s/mile which is almost 3 min over a marathon.
I would take this with a large pinch of salt at the moment. They haven’t talked much about how much uncertainty there is in their results, but if you look at the third figure (the one entitled “Estimated change in race time, compared with a previous result, when switching shoes”) you can see that the 95% confidence intervals for their estimate of the change in race time associated with changing to the Vaporflys overlap a lot with the 95% CIs for several other shoes, in particular the streaks. A rough rule of thumb in statistics is that if the 95% CIs for two estimates don’t overlap than those two estimates are significantly different*. Here we have lots of overlap with some other shoe models, most notably the streaks but also Newton Distance and Asics DS Racers and then a bit less overlap with a few others as well. What this means is that although the patterns in these data are suggestive of an increase associated with the Vaporflys, we don’t have much confidence in how big that increase is and indeed, whether the apparent increase is reflective of a real effect or just a sampling artefact. To put it another way, the difference between the Vaporflys and some of the other models is not statistically significant** - you might note that they don’t mention statistical significance anywhere in the article even though it’s quiet technical in lots of other ways. Their statement that “Including the uncertainty around the estimates, the Vaporflys are a clear outlier, one of the only popular shoes we can really say makes any difference at all.” is misleading, IMO. If I tried to put something like that in a research paper I would get absolutely destroyed by the reviewers.
Cheers
Rob
Yes, I know you can still have a significant difference and see a small amount of overlap. Not as much as we see here.
** Yes, I know mindless null hypothesis significance testing is evil. Let’s not argue about that here.
Fascinating stuff. From a personal perspective, I absolutely love my 4%s, and I’ve PRed in every race I’ve worn them for.
2016 London Marathon (On Cloudracer) 2:42:16
2016 Vitality 10k (Brooks T7 Racer) 33:08
2017 London Marathon (On Cloudracer) 2:35:17
2018 London Marathon (Nike 4%) 2:27:56
2018 Vitality 10k (Nike 4%) 31:32
I will admit that I’ve stepped up my training considerably over the past few years, but I wasn’t expecting to knock another 7 minutes off my marathon time this year, and I’m positive that the shoes made a difference. I felt fresher than ever at the finish and my feet didn’t feel like they’d taken a pounding. A rather soft 10k road time also improved significantly. Also wore them for a 30k trail race recently and knocked a few seconds off the course record (which was when the course was slightly easier) which had stood for several years.
If you can get your hands on a pair, I would thoroughly recommend you to!
good stuff ,but in all fairness i felt that in almost every 2nd paragraph they say that their results are not certain.
and to be honest nobody would expect big differences in shoes so i dont think there is anyway to come to a clear result . but there is some trends.
I would take this with a large pinch of salt at the moment. They haven’t talked much about how much uncertainty there is in their results, but if you look at the third figure (the one entitled “Estimated change in race time, compared with a previous result, when switching shoes”) you can see that the 95% confidence intervals for their estimate of the change in race time associated with changing to the Vaporflys overlap a lot with the 95% CIs for several other shoes, in particular the streaks. A rough rule of thumb in statistics is that if the 95% CIs for two estimates don’t overlap than those two estimates are significantly different*. Here we have lots of overlap with some other shoe models, most notably the streaks but also Newton Distance and Asics DS Racers and then a bit less overlap with a few others as well. What this means is that although the patterns in these data are suggestive of an increase associated with the Vaporflys, we don’t have much confidence in how big that increase is and indeed, whether the apparent increase is reflective of a real effect or just a sampling artefact. To put it another way, the difference between the Vaporflys and some of the other models is not statistically significant** - you might note that they don’t mention statistical significance anywhere in the article even though it’s quiet technical in lots of other ways. Their statement that “Including the uncertainty around the estimates, the Vaporflys are a clear outlier, one of the only popular shoes we can really say makes any difference at all.” is misleading, IMO. If I tried to put something like that in a research paper I would get absolutely destroyed by the reviewers.
Cheers
Rob
Yes, I know you can still have a significant difference and see a small amount of overlap. Not as much as we see here.
** Yes, I know mindless null hypothesis significance testing is evil. Let’s not argue about that here.
