Voluntary control of agonist premotor silence preceding limb movements of maximal effort.

The ability to gain voluntary control over agonist premotor silence through electromyographic (EMG) feedback was examined in healthy subjects performing maximal horizontal elbow flexions. Subjects exhibiting premotor silence on at least 50% of the pretest trials showed significantly greater peak angular velocity than subjects who produced the silent period on fewer than 20% of the trials during the pretest. The latter subjects acquired control of agonist premotor silence with practice and graphic feedback regarding their EMG patterns. The subjects who were the most successful in learning to produce the silent period increased their angular velocity to the level of the subjects who naturally exhibited the inhibition. The less successful subjects showed smaller increases in velocity. The data provide further evidence that premotor silence is primarily under central influence, that its control can be acquired, and that it may be functionally related to contractile rate.