I'm training a fourteen year old, 8th grade girl who has a 5:39 mile. She has been running track/xc for the last three years, average mileage at about 18 miles per week, although PR was run while adapting to steadily increasing mileage (first week at 35 miles). She is 5'4", 105 lbs, fairly developed. Besides that, she does the bare minimum of strength training, one to two days of fast work, mostly short (5 or 6 by 400 at most). Most mileage is logged at 8:00 pace on treadmill or flat roads. What can I do to get this girl to the next level? What potential does she have for high school? How should I adjust her training? I am generally a sprint coach, so I am a little uneducated on this sort of thing.