Stepping in persons poststroke: Comparison of voluntary and perturbation-induced responses

Objectives To examine the stepping performance during voluntary and waist-pull perturbation-induced step initiation in people with chronic stroke. Design Repeated-measures single-case design. Setting University-based research laboratory. Participants Community-dwelling stroke survivors (N=10). Interventions Not applicable. Main Outcome Measures Ground reaction forces and kinematic data were recorded to assess anticipatory postural adjustments (APAs) and step characteristics for both voluntary and induced stepping conditions. Results Induced stepping was performed with both the paretic (35% trials) and nonparetic legs (65% trials). Induced first steps occurred earlier and were executed faster than rapid voluntary steps. Compared with voluntary stepping, induced first step APAs were shorter in duration. Step height was higher with the nonparetic leg for both stepping conditions. Use of the paretic leg increased (52%) during the diagonal perturbations that passively unloaded the stepping limb compared with the use of the paretic leg (33%) for forward perturbations. Conclusions The results indicated differences in executing voluntary and induced stepping, and between the paretic and nonparetic limbs in individuals with chronic stroke. The findings suggested guidelines for using stepping as a component of neurorehabilitation programs for enhancing balance and mobility. Additional larger-scale studies remain to be undertaken to further investigate these issues.