Major Muscles and Actions Involved
The supinator and biceps brachii are involved in supination, whereas the pronator quadratus and the pronator teres are involved in pronation. In supination the palm of the hand is turned upward while the elbow is kept bent, preferably at a 90-degree angle. In pronation the palm of the hand is turned downward while the elbow is kept bent at approximately a 90-degree angle.
Muscles in Action
Of the two movements, pronation is more important in most sports actions. However, to keep the muscles in balance, the supinators must also be adequately developed. Pronation is used in almost all hitting and throwing wrist and hand actions, as for example, in baseball pitching, football throwing, baseball and softball batting, racquet sports forehands and overheads, and in the golf swing.
Important Facts to Know