Oh, brother (palm face). HWGA, HWGA, HWGA - prattling on about our own small-sample test results, trying to fit them to our personal models of what we wish was true, and demanding "proof" in the form of other pseudobabbling, mental-masturbatory research if something doesn't support our view. I do it too. But you miss ***the principal point*** (see below), which provides proof concerning the original topic.
you are stating generalities
What's wrong with that? It's a generality that people tie up somewhere near the finish of an 800. You'd like to know if it's at 689 meters or at 742 meters, but the thing we know is true is that they tie up. Not knowing exactly where and when doesn't make the general observation any less factual.
In that vein, I don't know the figure for what percentage of PCr is exhausted in the first 87.932 meters of the 800 (or are you insisting the value for the first full 100 is the important value?). But I do know that Paul Gastin (who has contributed to research on the accumulated oxygen deficit method for measuring contributions of different energy systems to exercise) and colleagues have found that the contribution of the ATP-PCr system is negligible (and remains negligible) after the first 20 seconds in supra-maximal 90-second all-out efforts and after the first 25 seconds in constant-intensity exercise at 110% of VO2max (the latter test often lasting over 3 minutes). I can't imagine there is significant regeneration of PCr (if any at all) during an all-out 2-minute event like the 800, especially with the associated low muscle pH. Yes, "negligible" and "significant" are more of those irritating generalities, but Chuck U. Farley sez: "Who Cares? Contribution from phosphocreatine after the first 25 seconds of a hard 800 ain't squat."
That's the best I can offer at the moment. Finding sources might take time I don't have this weekend. The articles might require subscription anyway.
what has that got to do with the physics aspect ???
It doesn't matter, as you should soon see when we arrive at ***the principal point***.
We post this crap on here and we can often all be "right" as far as presenting data and citing sources, except that when we try to interpret the data, we're making assumptions and conjectures.
F'rinstance, the stuff I posted about the contributions of various energy systems and the time frames involved is correct (as far as we currently know). The part you alluded to about how phosphocreatine can resynthesize with enough available oxygen is also correct (although it won't resynthesize during an effort where muscle contractions are forceful enough to create ischemia and reduce available O2, but blah, blah, blah). What is a guess - not SWAG, mind you, but a very reasonable guess based on actual data - is that people normally positive split their best 800s in part because it's advantageous from an energy distribution standpoint to get the ball rolling early when 800m velocities are involved. Yes, it's partly a guess - theory, you might even say - but let me repeat ***the principal point***, since it seems some people aren't getting it ... (wait for it) ...
THEORY IS BUGGAR-ALL.
What is not a guess is that an overwhelming majority of serious competitors have historically run their fastest 800s with positive splits. Nor is it a guess what the average slowdown on the second lap is (or, for that matter, on each successive 200, since enough splits are available to figure out that tidbit as well). As is the case 100% of the time, when I type something about real-world application, that's the way it is. Not because I say so (although that will be good enough for you, if you have any sense), but because that's the way it already was. I just gathered the data and then said so.
Oh, wait - I think I hear that verse again. Come on! You all know the words! ...
THEORY IS BUGGAR-ALL.
So here's what I'm going to suggest to any butt harlequins, glute jesters, rump fools or ass clowns who honestly cling to the imbecilic fantasy that most 800m runners would run better if they'd only employ even splits or some "perfect formula" based on iron-clad rationale using fizzix ...
Let's gather a couple of hundred career-best 800m times from the really deep all-time list at tilastopja.org, ferret out the ones that have intermediate splits available (might take some digging) and see what we get, m'kay? I say we get the astonishing surprise (cough, sarcasm) that most of those performances were done with positive splits. So hang on ... what's the matter with those incompetent, self-sabotaging might-have-beens? Didn't they know they were just spinning their wheels by getting out ahead of the pace they'd average? Surely after dozens of 800m races (or perhaps more than 100) during a career (not to mention watching hundreds or thousands of other competitors and trying to learn from those races as well as their own), they would have by chance run (or seen) a couple of "perfect" races where they hit upon the "lawz o' fizzix," avoided those unprofitable positive splits, and figured out even or negative was the way to go. Amirite?
(subliminal message follows)
THEORY IS BUGGAR-ALL.
Know what else I'm willing to bet on? The average slowdown of 3% for each successive 200 (within 0.2%). And just why am I sooo confident that will be the case? That's right! You get a gold star! It's because I cheated and already crunched hundreds of these numbers over the years and they always turn out the same! Did it with high school and college runners as well as internationals, too. You just don't wanna take that bet (or any other one) against me, Chief Spread Eagle. Why, that would be like calling my all-in wager, me showing A-K of spades, watching Q-J-10 of spades hit the flop and insisting you be allowed to keep betting additional cash on your own worthless hand. That's pretty much what people do around this place, though, and it all amounts to bringing a ... well, nothing ... to a gunfight. Yeah, you already know the answer to this one. Everyone knows it. Most people run their fastest 800s with positive splits. If you've hung around track meets for even 5 seasons, you can eyeball this bad boy without having to go to any deep lists for validation, and it turns out your eyeball is right. If you only watch 800s on TV or video, you might see more championship rounds and finals which go out slower than a rabbitted record attempt, skewing your perception on how optimal fast 800s are normally run.
How yeuh say, wan more time-a, daffy English kaniggits! Zees wan ees for yeur mothair! ...
THEORY IS BUGGAR-ALL.