Symmetry Is Associated With Interlimb Coordination During Walking and Pedaling After Stroke.

Abstract

Asymmetry during walking may be explained by impaired interlimb coordination. We examined these associations: (1) propulsive symmetry with interlimb coordination during walking, (2) work symmetry with interlimb coordination during pedaling, and (3) work symmetry and interlimb coordination with clinical impairment. Nineteen individuals with chronic stroke and 15 controls performed bilateral, lower limb pedaling with a conventional device and a device with a bisected crank and upstroke assistance. Individuals with stroke walked on a split-belt treadmill. Measures of symmetry (%Propulsionwalk, %Workped) and interlimb phase coordination index (PCIwalk, PCIped) were computed. Clinical evaluations were the lower extremity Fugl-Meyer (FMLE) and walking speed. Associations were assessed with Spearman's rank correlations. Participants with stroke displayed asymmetry and impaired interlimb coordination compared with controls (P ≤ 0.001). There were significant correlations between asymmetry and impaired interlimb coordination (walking: R2 = 0.79, P < 0.001; pedaling: R2 = 0.62, P < 0.001) and between analogous measures across tasks (%Workped, %Propulsionwalk: R2 = 0.41, P = 0.01; PCIped, PCIwalk: R2 = 0.52, P = 0.003). Regardless of task, asymmetry and interlimb coordination were correlated with FMLE (R2 ≥ 0.48, P ≤ 0.004) but not walking speed. There was larger within group variation for %Propulsionwalk than %Workped (Z = 2.6, P = 0.005) and for PCIped than PCIwalk (Z = 3.6, P = 0.003). Pedaling may provide useful insights about walking, and impaired interlimb coordination may contribute to asymmetry in walking. Pedaling and walking provide distinct insights into stroke-related impairments, related to whether the task allows compensation (walking > pedaling) or compels paretic limb use (pedaling > walking). Pedaling a device with a bisected crank shaft may have therapeutic value.Video Abstract available for more insight from the authors (see the Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A365).