Transcallosal Control of Bilateral Actions The corpus callosum is an important neural structure for controlling and coordinating bilateral movements of the upper limbs; however, there remains a substantial lack of knowledge regarding its association with lower limb control. We argue that transcallosal structure is an integral neural mechanism underlying control of the lower limbs and callosal degradation is a key contributor to mobility declines. Corresponding Author: Brett W. Fling, Ph.D., Assistant Professor – Health and Exercise Science Department, Assistant Professor – Molecular, Cellular & Integrative Neurosciences Program, Colorado State University, (970) 491-3451; Brett.Fling@colostate.edu Disclosure of funding: This work was supported in part by funding from a National Multiple Sclerosis Society Pilot Research Grant (PP-1708-29077) and a David Mahoney Neuroimaging Grant from the Dana Foundation. Conflict of interest: The authors have no conflicts to report. © 2019 American College of Sports Medicine