Ive noticed a few things about almost all of my artwork, the poses (among other things) doesn't give off the feeling of energy I want it to and then it ends up looking like crap. Another thing is anatomy, no matter how much I study and practise, the bodies don't come out the way I want them to. Here's an example Attachment 555748
In the second picture, his knees are way to low, his right arm (or the left, depending on how you look at it) looks very static and isn't doing anything. Those are just typical things I've noticed, anything else you find odd or out of place, let me know.
So my real question is, what kinds of exercises should I do in order to improve on anatomy ?