Here's my calves assignment. I think my weak points in these drawings are not splitting the shading into light and shadow as much as I could, needing more structure and indications of perspective of bony forms and tendons in some areas, and there are some proportion problems in some of the studies.

I don't think that anyone in their right mind would blame an anatomy master critiquing another anatomy master. Old masters were people too, with flaws. I don't like this awe that we have on their works nowadays. Then again, I'm just another person trying to improve my anatomy, so my opinion barely matters, but let's relax a little, and be happy that the arts are improving with every passing year :)