Improved gait symmetry in hemiparetic stroke patients induced during body weight-supported treadmill stepping

Background: Body weight-supported treadmill training (BWSTT) is being investigated as an adjunct to conventional gait training for the treatment of hemiparetic stroke patients. The potential efficacy of the technique may, in part, be related to optimiz-ing locomotor-related sensory inputs to the nervous system, which in turn may improve the timing and coordination of motor activity. Objectives and Methods: This pilot study evaluated the effects of varying two types of sensory inputs, limb load and treadmill belt speed, during BWSTT. We assessed the effects of three levels of body weight sup-port (BWS) and three treadmill speeds on the single limb stance time ratio (SLSR) and the single limb loading ratio (SLLR) in four subacute hemiparetic stroke patients. In three additional subjects, we studied the effects on SLSR of changing only the level of BWS at the one treadmill speed equal to best overground speed. Results: In comparison to overground walking, treadmill walking increased the SLSR toward 1.0. Higher belt speeds generally did not alter this increase in symmetry. A significant rela-tionship was also found between SLLR and BWS. Fifteen percent BWS was most often associated with a SLLR close to 1.0, independent of the treadmill speed. Conclusion: During BWSTT, the moving treadmill belt entrains greater symmetry of single limb stance time in hemiparetic subjects who otherwise step asymmetrically. Optimal limb loading and treadmill speeds can increase the symmetry of stepping-associated sen-sory inputs, which may enhance the locomotor output derived from activity-depen-dent plasticity. Key Words: Body weight support—Treadmill training—Stroke— Hemiparesis—Gait training