The top half of her body is incredible, but from her navel down it seems off. Her pelvis is squashed vertically, and legs... don't work that way. It's a really difficult pose and angle, so it's hard to say how to correct it, but I tried finding similar references so you might be able to see for yourself.
That's what I was thinking when I first saw it. The hands might be over-perspectified, as well, while the legs don't have quite enough perspective to keep things proportioned right.
I'm going to consult my library of poses (old drawing / sketch reference books) and see if I can't find something that fits...