I'm one of those people who progresses extremely slowly with my art, but believe it or not I've been studying anatomy and I've taken all sorts of courses (albeit mostly free, because broke) for over a decade, when I got more serious with my art. My skill level isn't anywhere near yours I'd say, but I know the grind of "well now I have to memorize how this particular weird joint/muscle/tendon combination looks".
I think it'd be hilarious seeing them attempt yoga or something like that, lol. But yeah, I have two entire sketch books absolutely full of various people in yoga poses. It really pushed my knowledge on how the body moves and I had such badly stiff figures back then. It's really great practice for any skill level.