Jap wrote:
Where in the world did you get that out of what I said? Her best lap pace for mile is usually around 56, she can't hold that for another lap.
Again, I don't understand your argument because you keep referencing this 1:50 time. No woman is ever going to run that fast. But many women run 49 every year.
If she trained for sprinting she would not automatically carry the endurance from her 3:50 because she is over taxing her reserves in a 400m, way beyond what she uses to pace for a mile, so your projections are way off. She would be just like other runners in that event.
Per the all-time lists, no woman appears to have run both sub 50 and sub 4:00 in the 400/1500.
I imagine the reason 1:50 was referenced in the original post was that you would expect an individual capable of both 49.xx and 3:50.xx to be capable of running 1:50. In fact, we generally see a couple 49.x/3:50.x high schoolers each outdoor season. It's not an uncommon line.
Dibaba's the fastest woman ever over 1500m, but why do you think that translates to a sub 50 quarter? The physiological demands between the 1500 and 400 are about as similar as the physiological demands between the 1500 and half marathon; success in one no way guarantees (and to some extent probably hampers) capability in the other.