I coach a small relatively rural high school team and one of my seniors this past couple years has caught the running bug, upping his mileage on his own over the various off seasons and covid. He's not supremely talented in any way, except he does seem to be very durable.
He's built up to 80mpw consistently before but I have him running between 65-70 right now that we're getting into racing season and workouts. He's been doing various tempos over the summer, with strides and hills and a couple road races mixed in. He's improved a lot, finishing XC last year as a 17:50 guy and he's run ~16:45 this summer. I just feel like he should be improving more based on the amount of work he has put in.
I've talked to him about sleeping and stuff and will keep reiterating that into their heads, but I've started this thread more for training talk.
I myself am much more fast twitch and most of the other boys on our team are decent (low 19-mid 17), but they are all significantly under developed aerobically compared to the above 16:45 runner. I haven't really coached someone like this before and wonder if anyone had any workout tips or anecdotal experiences? I fully believe he will improve regardless, but I don't want to force him to train like the others at the detriment of his potential down the road.
tl;dr I have a slow twitch kid running 70 miles a week and need advice on how to train someone like this rather than my usual aerobically under-developed high schoolers.