This is an old photostat from Disney that concerns "follow through". also known as "overlap" or "secondary action". My wife worked in the clean-up department at Disney and years ago she bought this from an animation art dealer. I think there's great drawing info here for animators and anyone else who draws.
If you don't know about this concept, it basically concerns things like hair and clothing. Anything that isn't a living form on a figure, but is influenced by the movement of the figure it's on. If you take a peice of ribbon and run around the house with the ribbon trailing behind you, then the ribbon is a good example of follow through. If you look at the ribbon and study it you might be surprised to see that the movement of it isn't random - it repeats the same action over and over. There are patterns to overlapping action that make them easy to analyze.
When I was animating for a living, there were some animators that would leave off the secondary action until they had worked out the action (and the acting) first. Then when the director approved the scene they would go back and add the hair, clothes, etc. Or even have an assistant do it for them. That way you're focusing on the most important part of the scene first without worrying about the secondary action.
Nothing wrong with this of course. Personally I couldn't do it, It drove me crazy because it always looked stuck on if you added it second. And drawing a bald or naked character just always looked so lame I couldn't bear to show it to a director. And as I've said before, for me my drawings have always been best when I conceived them all as one thing. Each drawing is one design in and of itself. How can you add later and have it still look good? This is why I don't use a Cintiq at work - it encourages you to work and rework each part of a drawing seperately. I hate that! If I don't draw it all as one thing (including background and all the characters all at once) then I never like it. I tend to draw really fast and the Cintiq and Photoshop can't seem to keep up with me...but I digress. This post is supposed to be about follow through!
Check it out and ask if you have any questions.