Once I read in one of R. E. Hale's books something to the effect that the problem of representing motion has never been fully solved. One usually deals with repetitive motion, for instance, by placing the actor either at the beggining or at the end of that motion ( right at the instants, therefore, when he is in fact standing still). One never draws a man banging on a nail while the hammer is actually halfway down, but rather when the hammer is at the top of its path or has just hit the head of the nail. Our knowledge of the action completes the picture.
Another way is just not to choose, and actually draw the hand, the arm, the body, at various positions throughout the motion, superposing all such drawings on the same sheet. This is usually frowned upon as a comic strip technique, but I find that objection to be mere pedantry. There are a lot of artistically valid solutions stumbled upon by comic book artists over the years. They, unlike some oh-so-modern breed of artists, are at least keeping up with one of Michelangelo's main commandements: Shut up and draw a lot!
(Btw, yes, this is (was supposed to be) you, M. Thanks for the invitation :))
