Rationale: The Balance-Based Torso-Weighting (BBTW) is a patented evaluation system that uses strategic placement of small or lightweight weights on the trunk to improve balance and stability. BBTW has been found to improve the upright mobility of people with multiple sclerosis, however the mechanism underlying the improvement of balance and gait is still unknown.1-2 Purpose: The purpose of this study is to investigate the immediate effects of BBTW on muscle activation of tibialis anterior and gastrocsoleus and sway using electromyography and force plates during balance tests in people with MS and healthy controls?