I've never had any problems doing it until lately, but now every time I do it, it causes searing pain in my quads. When it doesn't, it just makes my legs so weak and watery that I have to stop dancing and shake 'em out or else risk falling on my face. Two weeks before Thanksgiving, I tore one of the muscles and couldn't even walk for a couple days (forget about dancing for the whole month of November). Even doing them slowly and not-sharply, my legs still feel weak. This is obviously a BAD situation.
So, my question is, what is a good exercise to do to improve these? I'm not sure if it's a problem with flexibility or strength. I've been doing plies (25 in 1st, 25 in second, with all sorts of releves thrown in) every morning. I've also been doing this one where I kneel in leap position (sitting on one heel with the other leg out in front). Neither one of those seems to be helping much. I've had to take them out of my steps and the replacements don't look as nice.
So, any advice you guys can provide?