Quote Originally Posted by scottmitchell74 View Post
Fascinating! What do we make of this? Ryun and Wottle both ran 1:44.3 decades ago. Is this the fastest an 800 can be run w/negative split? What if Rudisha in London went out 50.5? Could he have come home 50.4?

Love this kind of thought experiment/debate. Why are the 400 and 800 the only distances where the WR isn't regularly run with negative splits?
I believe it has to do with the predominant energy systems for each though I am certainly not a sports scientist. The lactic system though not the sole supplier of energy is important for both. Those events are closer to (along with 400mH for outdoor events) 50%-50% aerobic/anaerobic respectively than any other events. One study has the 400m as 41/59 for males 45/55 for females and 800m as 60/40 for males and 70/30 for females.