Before I start this critique I want to ask one very important question. Do you use circles and stick figures as the base of you drawings? If you don't I would definitely suggest that.
Her action motion doesn't seem smooth or natural. Action poses are difficult. To help improve your poses I would suggest you ask a friend or sibling to pose for you. Take a few reference pics with your camera and work from those. This way you can see the way the body naturally flows. I read somewhere that the body is like dominoes stacked in a line. If you knock one over they all fall into place. Well, with the body if you move one limb in one direction the body will move elsewhere to make it feel natural. If that makes sense. (The book explained it SO much better.)
I noticed that you made her clothes and hair kind of move with her action. Which is really good. That helps add a lot to the drawing. You also did a good job at adding shading to this. This gives the drawing depth. Although it doesn't look like you picked a certain light source.
I hope my critique was helpful. I try really hard to give an honest and professional opinion. I hope you don't mind. Keep DRAWING!!!