Excitation overflow: an electromyographic investigation.

The amount of excitation overflow into a nonactive upper limb can be predicted when the active limb is isometrically contracted during a standardized exercise. Bilateral electromyographic recordings from the biceps brachii and brachialis demonstrated that the amount of excitation overflow in the nonactive limb is between 10 percent and 20 percent of the maximal intensity of activity measured in the exercised limb. This amount appears to be independent of the position of the active limb (supination, neutral, or pronation) and the amount of force used during the isometric contraction exercise. Excitation overflow, using the exercise described, should be considered as a reliable rehabilitation technique for maintaining a degree of muscle tone and tissue turgor in a limb that is temporarily immobilized.