Doing It Right
Not all high-level athletes look alike. Nina Matsumoto has a page full of pictures (photoshoot by Howard Schartz and Beverly Ornstein) of Olympic-level athletes that exhibits an incredible range of body types.
athletic body diversity reference for artists is an excellent resource for people who want to draw physically capable people fitting a large number of body types.
Showing How It’s Done
SenshiStock is “a deviantART account full of pictures of people. These pictures are here as a drawing and art creation resource. They can be used for anatomy help, pose reference, help with drawing perspective, and much more!”
Realistic figures in various poses and caught at various points of movement, so people can see what it actually looks like. Maybe this will help avoid the Escher Girls — as amusing as they are, I like how real people look.
Doing It Not Right
I really should have pointed out Escher Girls at the same time. Ami Angelwings has an entire blog dedicated to pointing out the stupid character designs and poses sadly common in comic books. Other sources as well, but most comic books because it’s possible to draw people in positions not actually possible in real life.