Animating a figure moving away from camera into the distance is not as easy as it looks.
Here are the drawings, rough background, and x-sheet for the Joker running away in perspective. The final color version in the commercial was tilted counterclockwise approximately 15 to 20%. It was also a little shorter at the end, cutting just before the Joker lands after he clicks his heels. (see the Joker commercial clip in my post from Saturday, July 30, 2011 "Batman Zellers Commercial Series")
Study the x-sheet. You'll note that the original timing had the Joker taking 8 frame running steps. However, that was too slow and the Joker could not possibly cover much distance at that jogging speed for the time allotted in the scene. So, I animated him running at twice that speed (4 frame steps).
Note that I originally timed him to kick his heels together on drawing 40 & 41. I changed that in the animation to heels clicking together on drawing 38 and seeing him "float" in the air with drawings 39 to 44. The heel clicking is a passing "squash" into the "stretching" of the legs apart for 6 frames, which is what sells the action.
An interesting timing exercise is to:
1) expose all the drawings on 2 frames (doubling the scene duration);
2) expose the drawings in combinations of 1 frame and 2 frame exposures. You can expose all the drawings where the Joker lands on the ground for 2 frames and also do the same for the "floating" drawings.
You will see how the action will feel different with these varied timings. How you expose the drawings will have a subtle but definite effect on the scene.