I did leave room for Rudisha's 800m, when I said "among others".
My thinking in starting this thread was like Body Master's--most significant, as opposed to most impressive, beautiful, deserved, publicized, etc.
Rudisha's was great for all the reasons mentioned already, but in the end it was only an excellent performance by someone who was widely believed capable of delivering said performance on the big stage, and it was only very incremental in terms of the WR. Probably the only twist to his WR is that he didn't have a rabbit. Plus, it was his own WR he was breaking, it was a very recent WR, and it was only slightly ahead of Kipketer.
Like body master was saying, significant should change the way we think about things, or it should change the landscape. That's why I voted for Blake 19.26 last year.
Any time a massively doped, super-old women's record goes down, that is super-significant, especially when it is either a power event, or a Chinese/East German/East European record. We all know how old those records are, and that there have been truly great athletes to come along throughout the years, both juiced and not, who haven't been able to touch those times. Marion and Jeter never got the 100. Perec and Felix never got the 200. Not even Semenya has touched the 800. The records are all so ridiculous, that many have proposed wiping them from the books.
But what about now that one of them, a big one, has gone down--and not just by a little bit, but by a LOT? Over half a second! What does that tell women about the rest of those records?
Face it, WR's are a very psychological thing. Half the battle is people believing they can be broken. All the women's records have been dismissed as unbreakable--but guess what? Apparently they're not. It is of course reasonable to believe that many of today's best women are juicing, but as yet we don't know if that juice is legal or not. The point is that whatever they are doing, they have proved themselves capable of matching or bettering those historic performances, especially if we are still relatively early in the history of whatever new techniques they are employing.
Look at Felix's 200. With the exception of VCB's handful of performances in 2008, and Stewart's 21.99 in 2008, all of the performances under 22.00 were done forever ago, and many by acknowledged dopers--names appear like Kratochvilova, Krabbe, Privalova, Wockel, Miller, Gladisch, Gohr, Dreschler, Ottey, Jones, Koch, and of course FloJo. The dates of the best performances are super-old, with half or more in the 1980's!
But now Felix is there. Yes, she is a mile away from 21.34, and all the other women are miles away from the 400, 800, etc. But the 4x100 proves it possible.
Just like Jeter's 100 times, which are equal to/better than all of FloJo's except for that 10.49 Jeter was there knocking on the door, and but for a faulty wind gauge, she would have the WR.
There are probably people who believe that the individual records are still unbreakable, notwithstanding the 4x100 WR, and given how far ahead they still are, it could be a good argument--but the best test is probably how the athletes see the records. They're getting closer, and have to now believe that they are possible to get.
Jeter could have gotten the 100 but for the wind gauge.
Felix is the best 200 to come along in a LONG time.
Felix might have the best shot at the 400, if she dedicates herself to it.
Look at the men's side: the 100, 200, 4x100, 800 have all gone, the only old records remaining are really MJ's.
IMHO the 4x100 WR redefines what is possible for the women, and that is why I picked it as the most significant performance.
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As for most "impressive", I was more impressed by Eaton's deca WR in the cold rain than I was by Rudisha's 800WR. Yes, Eaton had home field advantage--but have you ever tried doing a deca in the rain? I have. To set the WR under those conditions is nothing short of incredible, and it likely means that he will put it out of reach for a long time, if he stays healthy.
In setting it, he LJ'd to 14th on the world list year, TAKING ONLY ONE JUMP, in a distance that would have won him Olympic silver.
His LJ was a decathlon best, as was his incredible 10.21 100m, which would have qualified him for trials in the 100m, and which was only .03 slower than the Olympic A standard.
That same day, he ran 46.70 in a monsoon.
He did all that, AND got a WR at the same time.
No doubt Rudisha's 800m was impressive, but for my money, Eaton was even better.