In considering the phenomenon of throwing, one cannot pass over the remarkable difference in the manner of throwing of the two sexes. (…) The girl of five does not make any use of lateral space. She does not stretch her arms sidewards; she does not twist her trunk; she does not move her legs, which remain side by side. All she does in preparation for throwing is to lift her right arm forward to the horizontal and to bend the forearm backward in a pronate position. In the final motion, action is limited to the triceps and flexors of the hand. (…) The ball is released without force, speed, or accurate aim. It enters almost immediately the descending branch of a steep parabola. At the age of six, the girl tilts her right shoulder slightly and moves the left foot forward one small step, but shows no further progress. A boy of the same age, when preparing to throw, stretches his right arm sidewards and backwards; supinates the forearm; twists, turns, and bends his trunk; and moves his right foot backwards. From this stance, he can support his throwing almost with the full strength of his total motorium. The excursion of his final motion reaches an angle of 180°. It moves around the left standing leg as its central axis. The radius of this semi-circle exceeds by far the full length of the arm. The ball leaves the hand with considerable acceleration; it moves toward its goal in a long flat curve.
Erwin Straus, « The upright posture », Phenomenological Psychology (tr. Erling Eng)
