Mechanisms Responsible for the Age-Associated Increase in Coactivation of Antagonist Muscles

In Brief Age alters the control of voluntary movement. A frequently observed adaptation is the increased agonist and antagonist muscle coactivation. Here we examine the evidence for spinal circuits mediating this change in motor behavior and propose the hypothesis that cortical mechanisms also contribute to this age-associated change in muscle coactivation. In addition to spinal paths, motor cortical circuits also may mediate the age-associated increase in antagonist muscle coactivity.