Got beat in a 5K by someone doing 15 mpw. Basically all of their runs are workouts. It's got me wondering whats the point in running so much mileage?
(Yes I know this won't work for HM and marathon and yes some of you will think those times are slow).
He's probably runs much more than that, but is one of those people that loves to brag about "how much they achieved on so little effort." It's very common.
If running "bare minimum mileage, as fast as I can every run" worked, your local 5K would have everyone running 17 min. But it doesn't work, because 99% of casual runners are doing the "minimum mileage, as fast as I can" thing and they can't even sniff 17 min.
Even this is true, that your buddy ran 17:06 off "15 mpw, all out" that doesn't mean it'll work for you, or that he's achieving his potential. You probably need higher mileage, with the majority comfortably aerobic and a small percentage at moderate to fast pace, like the rest of us mere mortals.
Many of us can run faster than that without training but that isn't the method to do our best. If Grant Fisher gets tired of running and takes a few years off, he could show up at a random race and run 16 minutes looking easy. He could run 14:30 on 15 MPW easy.