Now that you've brought that up Virago, I vaguely remember reading something about the menstrual cycle and training, and I remember it being pretty damn interesting. I think it actually had something to do with joints... I'll have to see if I can dig it up. I don't remember too much about it, but I do remember stumbling across it when I was doing serious research way back when. It may not have been joints, but I'll look into it.
The Greatest Respect You Can Earn is Self Respect.