Is Kipchoge a 2:04' runner? (Dr. Ross Tucker on the Vaporfly)

Bekele, Berlin 2016. Check out those midsoles.

2:03:03.

Now let's see London 2016:

Look at his shoes. Look at Kipchoge's.

Of course the shoea don't tell the whole story, but they do tell something.

Following your and Ross' Tucker's logic majority of those who switched to VF should have improved by significant margin. So 2:04 marathoners should've become 2:02 runners, 2:07 runners should've started to produce 2:05 consistently and 2:10 runners should've been comfortably running 2:07-08 now. Yet you don't see this correlation.

Also pictures are not a prove of anything as long as you haven't got these specific shoes and tested them in lab with all variables controlled. Deduction based on pictures is speculation at best. Sample size is too small and you have too little data to make objective conclusions because there are many variables you don't take into account, like for example, nutrition.

Think about this for a moment. You have a function with number of different variables as inputs (nutrition, pacing, shoes, course, weather) that yield some output result. You input one set of variables and get Kimettos marathon result. Then you input completely different set of variables and get Kipchoge's marathon result. Somehow despite giving completely different sets of inputs you state that this one particular input (shoes) is the one that changes the yield of the function.

Alll wrote:

In 2016 Eliud Kiochoge ran 2:03:05.

Some people say that nike 4% makes elite marathoners run 3 min faster. If it is true, why Kipchoge haven't run 2:00:05 in London?

some people are dumb, like gary claiming EPO doesnt work. if you look you can see that them vapes give the top elites 1:30 for men and up to 3 min for women....

the real deal wrote:

Well if Kipchoge is only a 2:04 guy, that means the rest of the top guys, minus Bekele, are a bunch of 2:05-2:06 guys.

Plus Bekele too!

nv4 wrote:

Following your and Ross' Tucker's logic majority of those who switched to VF should have improved by significant margin. So 2:04 marathoners should've become 2:02 runners, 2:07 runners should've started to produce 2:05 consistently and 2:10 runners should've been comfortably running 2:07-08 now. Yet you don't see this correlation.

Show me the people that got worse? Or even stayed the same?

Different people will respond differently to the shoe. It's been reported several times Kipchoge responded particularly well to the shoe. Also, that Bekele didn't like it in the beginning (I guess he does now).

I see what you're trying to say. Many variables, sure, couldn't agree more. One argument that got me thinking, though, was this:

You get a mature and consistent marathoner like Kipchoge, who's already figured out the distance (6 marathons by then) and has the best training possible, who never ran faster than 2:04 until the new shoes. And now he runs 1-2 minutes faster consistently? Only in the hottest London marathon ever was he as 'slow' as he was pre-Vaporflies.

Don't you think it bears consideration that the shoes play a part? It's debatable how much of a part, and we're likely to never know, but it is obvious the new shoes are changing the landscape in running performance.

Wildhorse wrote:

God damn dude. Get a life. You're on here every single day obsessing about the Vaporfly.

You must be here everyday too.

As I already tried to explain it to you Kipchoge is not a benchmark. It's a one case study. In research case studies are among the lowest in terms of quality of evidence. If you want to make a claim at least do some statistical analysis on sample larger than n=1. And I recommend for Ross Tucker to do the same. To check if your claim have any basis let's check all sub-2:10 marathon results and compare how many of them were achieved each year in the last decade. If your claim is valid we should be able to see a significant increase in number of sub-2:10 results since 2016 when Vaporfly shoes were introduced. There have been recorded a total of 2921 sub-2:10 marathon performances. Here are the sub-2:10 performances by year in the last decade: 2019 – 180 (6.1%) 2018 – 171 (5.9%) 2017 – 186 (6.4%) 2016 – 146 (5.0%) 2015 – 167 (5.7%) 2014 – 196 (6.7%) 2013 – 173 (5.9%) 2012 – 197 (6.7%) 2011 – 174 (6.0%) 2010 – 158 (5.4%) As you see that is absolutely not the case. Since introduction of Vaporfly shoes in 2016 during span of 4 years we have seen 683 sub-2:10 performances or 23.4%. Just prior to introduction of VF shoes during the span of 4 years before there was 733 sub-2:10 performances or 25.1%.

Why do you choose that arbitrary time, 2:10? Why not sub 2:05 instead?

Why not get the top 100 marathoners, some of them running in Vaporflies but many of them in other brands, and compare their average finish before and after 2016? Wouldn't that be more revealing?

That's what you need, compare the improvement of those that adopted the shoe vs. others of similar fitness who didn't.

Kipchoge is one example, not proof of anything.

Why sub-2:10 and not sub-2:05? Because sub-2:05 is very small sample size, only about 200 performances during entire athletics history. In such small sample size a single result would give 0.5% deviation. This is huge variation as single race in good conditions could produce false positives of around 5%.

Why not get the top 100 marathoners and compare their times before and after 2016? Firstly, again the sample size is too small. Secondly, who have such data? I doubt that anyone have valid data pool for that with large enough sample size. If you have such data, I'll gladly do the calculations

I don't.

What's your take on the shoes, then? No benefit? Negligible? Impossible to know?

Are you in favor of limiting shoe tech?

When that shoe malfunction happened in Berlin in 2005 were those 4% prototypes he had on?

My personal take is that improvement has been widely exaggerated. I think the reason for this is mostly the result of spectacular performances shown by Kipchoge and Bekele lately. Also the two sub-2:00 attempts have somehow taken over our minds and have blown this all out of proportion when actually these two races are synthetically produced results that have little to do with real world performances.

That said I still think that Vaporfly shoes provide benefit but it's nowhere near the 2.7% claim. In reality from what I have witnessed in local races with top regional guys I have been competing together for years improvement has been around 0.5% but I think it's really impossible to know because there are so many variables involved.

Am I in favor of limiting shoe tech? I don't see significance to that as long as we have rule that shoes must be generally available to all. We can't compare today's results with historical performances anyway. Innovation is inevitable but it will be self limiting because at some point price margin will be so high and performance gain so negligible that it will limit itself.

+1

Very well said.