Anticipation, Action and Reaction are three of the main foundational principles of animation. Without them, your animation will appear to be mechanical and stiff.
If you are standing still on both your feet and you want to begin walking, you will start by shifting your weight from being equally distributed on both legs onto the one leg, let’s say your right leg. You do this so that you can lift your leg off the ground and move it forward in the direction you want to walk. This shift of weight is always in the opposite direction that you will ultimately be moving in. This is called anticipation. A slight movement in the opposite direction that your main movement is in. The anticipation gives a moment of preparation for the character, and the audience to gain the full advantage of the main movement.
Anticipation will add life to a characters otherwise mechanical movements. As a general rule, you should anticipate every move, even if it’s just for one drawing. There are subtle anticipations and there are broad ones. It depends on the character type, the mood,the situation, the action, and the emotion involved. A quiet character in a calm mood, pointing at something on a table, saying, “There’s your fork.” might have a 2 drawing anticipation with the hand moving back only one inch and then moving forward into an almost-but-not-quite fully extended arm.
A much more boisterous character in the same scenario but being much more exaggerated could rear back two or three feet and then move into a fully extended point.
Usually, the bigger the action; the bigger your anticipation should be.
Another example of an obvious use of anticipation is in a golf swing. If you try to move the ball without pulling the club back the ball won’t go too far, so you have to anticipate the hit by swinging the club back and then swinging through, hitting the ball. The same applies to shooting a puck with a hockey stick. Without an anticipation, you end up with a wrist shot which is effective in certain instances but is less powerful than a slap shot. The same general statement applies: the stronger your anticipation; the stronger the action.
As with anything in animation though, for every rule, there are many reasons to break it. Just remember my personal primary rule that overrides everything: “If it looks good, that’s all that matters.” or “It doesn’t matter how you get it done, just so long as it looks good.”
Drawing 22 is the halfway stretch inbetween and 23 is a tight favor into 24.
While the general mass of the character is at the halfway point, these other two parts are not. You can do this to add some flavor to certain actions. This just happens to be one of them. The mouth being open more adds impact to the expression and the hands being stretched do the same thing. The natural halfway point for these would be the mouth just slightly open and the fingers curling over. This type of an inbetween would soften the action and the impact of drawing 24 would be lost.
It’s usually the animator’s responsibility to indicate this type of an inbetween.