The text discusses the dynamics of body mechanics, illustrating how combining arm strength with body weight enhances power in movement. It explains the difference in body mechanics between pulling and pushing, emphasizing the role of body posture. Additionally, it describes how weight distribution affects balance when carrying loads.
THEORY
This plate XIX shows two men acting more powerfully than in the previous example, because here they combine the strength of their arms with the weight of their entire body, as well as the strength of the loins, legs, and calves. It also shows the difference between someone who pushes and someone who pulls: for pulling, in addition to the weight of the body, the strength of the arms is involved, along with the extension of the legs and spine, and also the muscles of the abdomen, more or less depending on how necessary the oblique posture of the individual is. In contrast, when someone pushes something, even though the same body parts are involved, the strength of the arms has no effect because pushing with an outstretched arm without movement is no more helpful than placing a piece of wood between the shoulder and the object being pushed.
Plate XX depicts various figures both nude and clothed in a running stance.
Figures Carrying Something
The shoulder on which a man carries a burden is always higher than the other, as if it were trying to rise against the weight pressing upon it. In all loaded figures, nature opposes on one side as much natural weight as there is accidental weight on the other side, so that the center of gravity, whether natural or artificial, must align perpendicularly to the center of balance: otherwise, the figure, unable to support itself, would inevitably fall.