If I had watched Buffy/Angel recently, I'd probably take a crack at it, even knowing my dubious humour-writing abilities :p

True, but it isn't as if she'd have an actual challenge, fighting against other human women, and a weight room can only do so much. So unless she regularly started all-out brawls/riots to get some practice (in which case, she'd probably spend a *lot* of time in solitary, and being watched by the guards :P), I don't think she'd be able to keep quite in top shape.