Just an observation - she isn't...pulling any arrows from that quiver.
Edit pending. I'm definitely not used to working on that scale!
before anyone says anything, this is a really quick and "dirty" edit here,
And i'm feeling a bit too lazy to add the pulling form the quiver mvoement so i just assumed she already had an arrow in hand.

The front leg movement makes it seem as though it's actually growing in size. if you're stepping forward , the rest of your body moves in tandem, it's not just that leg. if the other leg stays in the same place, then only the foot is going to do that, the rest of the leg will stay with the rest of the body. well more like the waist, but anyways,i'm rambling.
If you need a reference, look for a mirror and pose in front of it. observe how *you* move.
now as for archery in general, watch some youtube vids of archery. there are a few of them.
And just from my own personal experience, it's much easier to draw up a very simple model and animate -that- before adding in details, that way you've already got the motion down. chances are if the animation is fast/fluid enough a good number of the details are going to be lost anyway.