I’m doing something similar with a full body male anatomy study, just haven’t posted the work here yet. Some areas that I think would improve your model:
The hands are too thick, as are the fingers. I’d suggest forcing the bones out more than you think is necessary. Than smoothing it out slightly. Also the whole arms look too puffy, I think they could be scale down a bit y-axis wise. And they seem too short. My arms go to about halfway down my upperlegs. Yours goes about to the hips. I think it looks awkward to have heavy muscles and short limbs.
Does the model have skin or not? Its not apparent since on the face it looks like he has the start of older man’s face with drooping skin in the cheeks. His body looks like its hinting at a muscle study since your showing some of the muscle attachment points to the bones. This is very apparent in the knees. I don’t think you usually see the complete Sartorius muscle on weight lifters.
The lower eyelid is jutting out too far and should cling closely to the eyeball. Also trying using z-sub of 25 intensity. Mark your lines out on a higher division level than smooth those lines.At the edges of the lines you can than use a z-inflate tool with a intensity of 5 and puff up the muscles slightly. Just keep in mind that muscles are stretched and interlock with one and other frequently.