Funny how this thread just ended up being another Nike ad. For those of you convinced the shoe was responsible for Kipchoge'a WR, consider this:
The successful record attempt was not 4% faster than the slowest of his previous attempts. It was not the first time he wore those shoes. In them, he has yet to improve by 4% over any race he's run in non-4% shoes. He has never run (in any shoe) 4% faster than what he ran with the flapping-insole shoe. You may point out that the record run was 4% faster than the Gold Medal run (which, of course,I do not count as a record attempt above). The Rio run was in the 4% shoe and his slowest marathon yet. So upon what has he improved and by how much?
Rupp has not run a marathon in anything else, so has he improved by any amount, or is his PR about what Daniels, McMillan, and JK would predict based on 10km PR? Discounting Trials and Rio, What about the one perfect condition (judging by the women's winning time) marathon he's run in which his time was significantly slower than what any physiologist would predict? Also in the same shoe. Does he have any PRs that stand out above the rest when compared to the curve that Tergat's, Geb's, Farah's, or KB's PRs suggest is physiologically to be expected? No.
Whom has this miracle shoe proved by 2% even?