I am now 18, when i began running freshman year my mileage was pretty low and i had a decent cross season, (17:10 for 3 miles flat.) with no summer mileage and probably 30 miles a week in cross, cant say for sure....
at the end of the season i took about a month off then showed up to track ready to roll in december. I ran probably 40 miles a week that season( all training logs are now gone with my stolen phone) and cranked out a 439 mile which i was super stoked with. when i got to sophomore cross country i started running with the 'big dogs' on my team. after a couple weeks of buildup i was running prettty consistent 50+ mile weaks i would like to say. but the mileage was fast, often doing easy runs sub 6:50 and then we started high mileage early in the season. sophomore year I had a breakout season running 15:33 for a flat three mile. by the early october my shin was hurting and i tried to run a race. i found out i had a 6 week recovery from running on a stress fracture. after that I didnt get a very good base in for track and couldn't PR. so i came into cross country very hesitant. i completed the season with a lot of very very easy miles. not even close to my times from the prior year. the next track season i went to run with the varsity squad again and about halfway through junior track i had another stress fracture. to cut to the chase i tried to bump up again and ran a 15:20 on flat grass my senior year, and once more i got a stress fractrue after that. so this seaosn( senior track) i ran about 35 miles a week and all of my "easy mileage" was on a bike. with that i was able to go 4:30 the thing that bums me out is that i know if i run 60 miles a week i will be able to go 4:20 or maybe even faster. but i just cant seem to avoid these damn stress fractures.