“Doesn’t that contradict what you said earlier: However, every serious frum rov will simply tell you if you ask him, that in that case, you simply shouldn’t do that sport/activity. Obvious solution.”
No. It’s not a psak – more like advice (that’s how I prefer to interpret it anyway – call me a rosho if you want).
Fact is, most rabbonim I know are on a much, much higher madreiga than lowly me. I’m talking people who haven’t got a clue what “vacation” means or what “bein hazmanim” stands for and where kids have never heard of the word “camp”.