This is awesome and helpful. I've been hoping to do a (first time) animation, and have been trying to figure out where to start, and since it involves a character running, this gives me some perspective.
This is freehand. I get reference from myself or someone else and draw very loose to begin with, just to get the motion right. It's similar to gesture drawing. Then I go back in and start to get everything on model while adding in all the overlapping parts.