Young people are strange beasts for sure. It's useful to get good habits ingrained I guess, but they don't really need warm ups. I'm not sure adults do either quite frankly. It seems just going easy for a while before you get into the hard stuff is good enough.

Stretching is another thing. I'm old enough that stretching advice has gone full circle twice since I've been around. From ballistic stretching good to bad, long slow static stretching bad to good to bad again, and stretch before to only after to before and after again. And there was the craze for oppositional engagement for a while where you tense the muscle opposite the target muscle, and the reciprocal inhibition would allow a deeper stretch of the target. I don't know what to do a out stretching. I just know I hate it and do less of it than I should.

Anecdote meet singular data point.

Meanwhile, lifetime injuries from overtraining too young and agonizing pain. So… maybe we both choose medical data instead of what happened to our immediate singular data points.

Which… drum roll… says what the original guy said.

If you see my other comment the volume is actually where the risk lies. There is generally no problem with kids doing close to 100% VO^2^max or HR for extended periods. They'll just get pooped and quit before they can do any damage. It's the repetitive stress of 10s of thousands of foot strikes that can put immature tissues at risk.

Notably bones aren't fully calcified and growth plates are open at the end of the long bones. There isn't really a good understanding of what stress and exercise induced inflammation do to developing tissues...at least that I'm aware of.

Edited for autocorrect. 😡