Physical maturity - struggling with fitness as a male high schooler

In middle school, my son was undefeated in the 1500. As a freshman, he continued to improve and race well. Then, sophomore year, he naturally became much more muscular, broader shoulders, heavier. He continued to train, but was plagued by stress fractures -- I imagine due to the growth spurt and increased muscularity. It was extremely frustrating, as the rest of his high school "career" was a repeating cycle of great finess gains during the off-season and pre-season, followed by stress fractures and rehab during each competitive season.

I can sympathize with your experience. Best wishes going forward.

I suggest that you get a copy or an ebook of Training Young Distance Runners by Greene. You can buy the ebook and have it today on Amazon. It's been years since I read it, but I remember that it addresses these developmental issues and how to address them from the coach's perspective. You shouldn't have to read the entire book. Just skim it for the sections that apply to you.

OP, do you have a strength training, a jump or plyometric program routine? My experience is that you need one to prepare your body to deal with gravity and landing forces. Stepping down off low boxes, jumping onto low boxes, skipping, jumping rope and lunges, squat variations and dead lift variations appeared to have helped my HS athletes.

Are you doing upper body weight lifting? If so, it's possible you put on upper body muscle-mass that is creating extra weight to carry around. Or, since testosterone levels peak at your age, it's having an anabolic effect and putting on muscle mass throughout your whole body, which you alluded to. (Masters runners are frustrated by the opposite problem, but same effect). It's normal to be frustrated by this kind of thing. But it should eventually level off and pay off in performance. But it's going to take patience to train your body to utilize that new muscle mass in a way that translates into faster running. It'll happen. Just keep training.

I've been pretty diligent about lifting over the past few months (twice a week almost every week), but I never lift anywhere near my max (as no distance runner should with regularity). A sample workout would be something like 3-4x(12 squats) at an honest but manageable weight. The initial weight gain came over that summer, during which I didn't lift at all. Your conclusion is the one that I naturally arrived at as well, but it's difficult not to get frustrated with it.

I don't do any lifts/exercises that practice explosivity/gravity and landing forces beyond the occasional set of box jumps and/or explosive reps of dumbbell push press. The exercises you mentioned are ones that I probably should have been doing consistently for a while by now, but I'll try to start incorporating them now if I can.

Regardless I find it difficult to believe that the consistency over the past year has gone to waste, but clearly the benefits are laying dormant at the moment. I guess ideally they would manifest themselves in a period of rapid improvement past a certain point in my physical development, but I know better than to expect such things lol.

Just to clarify, I meant that this is a sample exercise. I obviously do more than a couple sets of squats during lifting sessions.