I'm a sprinter/sprint coach now working with a really promising 400/800 kid. Last year, he ran a 48.5 in his first attempt at the 400. He ran 1:52 in his 6th competition over 800. His training was pretty much random.
So many 800 programs involve long runs that are many many times the duration of the actual race. In what way does a 25-minute solid-state run help the 800 meter runner that a shorter, more specific run(s) does not?
Bear in mind, I'm coming from the sprint world. Theories differ there, but I think most people would agree that running at or near race distances 2-3x a week, with recovery or technical work in between, would hit most of what you're trying to hit for a sprinter. There might be good reason to go shorter (isolating block work or top velocity form), but not much reason to go significantly longer.
Why isn't this the case for an 800 guy? What do I lose if I have my guy do 3x600 slightly faster than race pace on some "hard" days, 5x1000 slightly slower than race pace on other hard days, and then just fill in the days in between with either top speed work, or maybe some lactic tolerance stuff.
Why would fairly specific work like this be suboptimal? Would he really suffer if he didn't engage in lots of runs that are (1) substantially slower than race pace, and (2) 10x the duration of the actual race?