Once I'm warmed up I'm ok, but going downhill to start the day, really gets my left knee. That's a Bball injury... skiing strengthens the quads/knees immensely, but I'd be lying if I didn't say there's some real wear-and-tear that happens too...
But [bleep] (now you got me bleepin', lol) just about everything worth doing takes a toll.
I've always been intrigued by martial arts but the injury risk spooks me, especially at age 45. I think if I could survive the first year or two relatively injury free I'd be ok, but getting into any knd of real sparring shape would be... adventurous.
