An electromyographic study of reciprocal activity of muscles

An electromyographic study of elbow flexors and extensors was conducted using 20 adult human subjects to determine if cocontraction occurred during voluntary movement. The interplay of proprioceptive reflex influences arising in the primary and secondary endings of the muscle spindle and in the Golgi tendon organ provide the neurophysiological basis for cocontraction. Whether or not cocontraction occurs during a movement is dependent on the degree to which one proprioceptive influence predominates over the others. This in turn appears to be dependent on factors such as those described below.