I just finished an anatomy class taught by Erik Gist. Mention anatomy and the eyes glaze over...it's dry and challenging. But solid anatomy is part of good figurative art. The class was based on drawings from Bridgman's Complete Guide to Drawing from Life. These drawings are rendered in Bridgman's scratchy style, but contain all the information needed to understand anatomy.
The directive to students was to draw fully modeled images based on these loose sketches. Get input from other anatomy texts if needed. Then, to reinforce the lesson, draw the same area using reference photos of athletes. We spent 2 weeks on each of 5 major areas (no head, hands or feet). As an example of the technique, see Bridgman's original leg sketch and my interpretation (below). I did about 40 sketches like this during the course. The approach is effective, and any motivated art student can train this way at home.
Our final assignment was to draw from memory. While my proportions were off (see below), I was surprised by how much anatomy I remembered. Still can't draw a perfect human form from memory, but next time I see a figure, I'll know the source of that bump or shadow, and draw it with more confidence.One other technique I finally figured out after 2 years of art classes is the "before-and-after" shot of instructor demos. Most instructors work directly on student work to demonstrate ways to improve. Next time it's your turn, photograph your piece before the instructor begins the demo, then again after they are done. Voila, personalized instructions for improvement. Study the photos. Apply what you see.
The "before" (left) and "after" (right) comparison below is from Erik's anatomy class. It shows me how to improve my shape definitions, especially obvious around the arm pits. Very helpful to know where I need to focus.