I don't know (I'm not a coach), but there must be something to this. Our kid did this with the distance team recently, and it just sparked a memory I hadn't thought about in a long time.
Back in the 90's, I was an above-average-but-not-great HS runner. Could have but never did run in college. There was an old coach in Columbus I got introduced to after my sophomore year at Ohio State; he helped coach kids who wanted to walk-on or fight for a scholarship at a local college. He reminded me of Mr. Miyagi, only running.
I met him at the track, and he asked me to do one thing. Warm up, and then run for 10 minutes on the track as hard as I could to see how far I got.
After I was done (I have no memory of how far I got), he told me he thought he could coach me down to about a 1:51 800m P.R. (1:57 PR in HS).
Workouts like this and the data good coaches gleam from them just fascinates me. I'll for sure pick the coach's brain; just curious if anyone had any thoughts.