Perhaps the animators out there already know about this resource, but just in case, check it out HERE. It’s Walt Stanchfields notes brought together in a tidy series of PDFs.
Walt Stanchfield was an artist who taught life drawing classes for animators with a special emphasis on gesture drawing. For each weekly class session, he wrote informal handouts to emphasize the theme of the current class session, to comment on work done in the previous class, or discuss whatever topic struck his fancy. Over a period of years, these notes were lovingly shared, studied, and treasured by animation students everywhere.
Mr. Stanchfield personally gave copies of his collection to interested students, and was happy to seem them distributed. According to many people who were lucky enough to study under him, he wanted to publish them as a book. Reportedly, the studio did not pursue this opportunity due to the difficulty of obtaining copyrights for the student drawings.