I think there's an elephant in the room with this article that is never addressed. While the data on the Vaporfly is certainly interesting, it has a state of the art midsole that doesn't last, a carbon plate, and a bunch of research behind it so, okay, may the 4% claim isn't completely nuts. (There are still reasons besides all this the data could produce out this result, and they admit it's not a perfect study.)
But... WHAT is UP with the STREAK???
Because if Nike's claim regarding the VF is that it makes you 4% more efficient, and low and behold this giant data set spits out 4%.... Why in hell weren't they saying the Streak makes you 3% more efficient? Because that ain't just whistlin' Dixie! (I'm sure it never occurred to them to check.)
Now, I'm not knocking the Streak as a racing shoe. People run in it, they like/love/okay with it. Great. (Kipchoge killed it in a pair that was falling apart.) But if that shoe was performing this well without any particular technological enhancement, then what is this study really telling us? I have no side on the VF issue pro or con as I've never run in them, but clearly there is a piece to this study we are missing.
So who races in the Streak? You feel 3% faster? ;)