There is a very confusing runner on my high school team. Last year he started off the season in the mid-20s, but brought his PR all the way down to a 16:49 at a fast course at sections and then ran 17:20 on a difficult state meet course. This year, he started the season with an 18:20 on a moderately difficult course. A week later he ran 17:22 at a really fast course. The following week he ran a 17:13 at a decent course (not super challenging but by no means a "grass track"). Then this week, he ran 17:10 on a VERY difficult course (probably 20-30 seconds slower at least than the previous weeks course and 40 or more seconds slower than 2 weeks ago). Last year he didn't train over the summer, but he talent really kicked in and showed late in the season. This year he DID train quite a bit over the summer, but is still showing remarkable jumps from week to week. Watching him it's hard to tell whether he will continue improving at this rate for a while or start to stagnate soon. What do you guys make of this?