Say a taller thinner distance runner (meaning he's not built like a sprinter but is taller than the average distance runner) runs the open 400 in 50.0. What kind of 800\1500 would you expect him to be capable of at 18 years old with relatively efficient training focused on the 800? Basically my question is how fast can someone who runs 50.0 get in the 800\1500 in highschool?