Immediately after the toes leave the ground, the knee bends slightly and the limb swings pendulum-like forward, then, as it nears the point directly under the centre of the trunk, it bends a little more and lifts the foot to clear the ground. After the limb has passed this central point under the trunk and is beginning to advance, it straightens out ready to plant its heel on the ground again. When it has done so it has completed the step, and the limb repeats the series of movement phases again for the next step.
Now, the limb of the other side has gone through the same movements, too, but the corresponding phases occurred alternately in point of time.
ILLUSTRATING THE ACTION OF THE FOOT IN ROLLING OVER THE GROUND.
One of these positions of the leg, that when it is bent at the knee so as to clear the ground as it passes from the back to its advancing movement forward, is rarely represented by the graphic artist in his pictures. The aspect of the limbs when they are at their extremes—spread out—one forward and one to the back, is his usual pictorial symbol for walking. But the position, immediately noted above, is an important phase of movement, as it is during its continuance that the other limb is supporting the trunk.
A movement of the trunk in walking that is to be remarked is its turning from side to side as it swings in unison with the upper limbs while they alternately swing forward and backward. It is a movement that animators do not always regard, since only an accomplished figure draftsman can imagine movement clearly enough to reproduce it. To describe the movement better we will consider it visionally.
SUCCESSIVE PHASES OF MOVEMENTS IN WALKING, ILLUSTRATING ESPECIALLY THE RECIPROCAL ACTION OF THE LIMBS.
We are looking at the walker from the side and see the trunk in profile—exactly in profile, of course, when the arms are at the middle position. As the near-side arm moves forward we see a slight three-quarter back view of the upper part of the trunk, then when the arm swings back we see the profile again, and with the arm moving still farther back, the corresponding side of the shoulder moves with it and the upper part of the trunk is seen in three-quarter front view. If the artist shows, in a walk, these particulars: (1) A three-quarter view from the front; (2) profile; (3) a three-quarter view from the back, and then carries them back and forth, he will add to the effectiveness of the screen representation. It gives to a figure, when slightly exaggerated in a humorous picture, a very laughable swaggering gait.
The arms were mentioned as swinging in a walk so as to help maintain the equilibrium. It will not be difficult to understand the phases through which they go if it is remembered that an arm moves in unison with the lower limb of the opposite side. This can be observed if one looks from an upper window down on the passers-by. It will then be noted how one arm as it hinges and oscillates from the shoulder-joint, follows the lower limb of the opposite side as it hinges and swings from the hip-joint.