Looking great! Solid study. I would suggest working on simplifying a bit. Maybe creating a more clear separation from light and shadow. I think the core shadow is super dark in comparison to the the rest. This makes it a little hard to read. The anatomy itself looks great though! You're on the right track!

I don't know leg anatomy, so take with a grain of salt, but is the lower right leg (his left) a little bubble-y? Also just my opinion but I don't like how the right leg (again, the model's left) is shaded darker than the other, but that's just preference. Nice work though.