I just now (funny how the brain works) remembered that I sent ~FablePaint (https://www.deviantart.com/fablepaint) an e-mail back in December with some art stuff after I was like "oh yeah! Dresden Codak's creator has an awesome Tumblr with some good tutorials for you ART people who do ARTS!" but I don't think she ever posted it on here (if she did, then I guess we have a repeat).
Also, make sure you click on the last link. It's the best resource for athletic bodies I've ever seen, in the sense that I never knew there were so many body types purely among physically fit people.
Dresden Codak creator Aaron Diaz's tumblr
http://dresdencodak.tumblr.com/
And some of his awesome article