Reminds me of a live study. And it seems this time as if you really picked out details that interested you the most. Did you crop it? The light in this one makes it appear more realistic than your other paintings i think. And the muscle structure(let's just call it that way) looks quite dimensional though it's vague. I'd be interested in seeing more of this subject.
Did you already find a piece which you'll paint on canvas? I kinda remember that being your plan. I only recreated one of my improvised pieces...ended up looking very different.
I've been using various brushes of late but for this one, I went back to a simpler brush I've not used since I began painting with SAI. The brush is good for details, forms and blending, but not so much structure, like the flat brush (which I typically use).
I've got stuff ready for painting, just a matter of doing it, which is more of a challenge than I'd care to admit.