I'm a rising high school senior hoping to break 15:30 in the 5k this cross country season. Last track season I ran 4:27 in the 1600 and 9:28 in the 3200 (also 2:05 800, clearly I'm a longer-distance guy). Freshman year I ran 17:09 in xc; sophomore year I ran 16:34; my PR, from junior year, is 16:09, but that was last September, and I think I am in better shape now. Do you think 15:30 is achievable, and do you have recommendations on the type of summer training (and regular-season training) that would help me get there. I've started doubling occasionally, and am trying to get used to 60mpw. I've run 70 mile weeks, but I'm in high school, so I don't want the volume to get too much higher than that. For summer training I've been mostly getting in easy miles on dirt with a fair number of hills (usually 7-7:30 pace). During the summer, about once a week I do a tempo, around 3-4 miles at 5:35-5:45 pace. I plan to do some longish intervals (1200s or 1600s) later in the summer, and have done some hill repeats and will do more, maybe every other week. Sometimes I do long runs or easy runs at 6:20-6:50 pace when I'm feeling good. I have done a couple progressive long runs, including one with the last 3 miles sub-6 and the last one in 5:37. I tend to run 13-15 miles for long runs; the furthest I've ever run is 20. I ran 10 miles in 59:30 solo one time just for "fun" (not a race or anything), so I think the endurance for xc is hopefully there. I did a 4x1600 workout in track season with all four at 4:57 or below, but the rests between were pretty long (probably 5-7 minutes). I think this will be a really good xc season, and I want to get the most out of summer training to be strong but not overtrained or at risk of burning out coming into the season. Any recommendations for workouts or what type of training to do would be much appreciated. How often should I double? How often should I take days off (if at all)? Ideal weekly mileage? Favorite workouts? Workouts that indicate 15:30 fitness? I know some people on letsrun give BS responses (that's part of the fun), but hopefully I get some real advice mixed in.