title: Treadmill exercise activates subcortical neural networks and improves walking after stroke: a randomized controlled trial.
abstract: OBJECTIVE
  Stroke often impairs gait thereby reducing mobility and fitness and promoting chronic disability. Gait is a complex sensorimotor function controlled by integrated cortical, subcortical, and spinal networks. The mechanisms of gait recovery after stroke are not well understood. This study examines the hypothesis that progressive task-repetitive treadmill exercise (T-EX) improves fitness and gait function in subjects with chronic hemiparetic stroke by inducing adaptations in the brain (plasticity).
  
  
  METHODS
  A randomized controlled trial determined the effects of 6-month T-EX (n=37) versus comparable duration stretching (CON, n=34) on walking, aerobic fitness and in a subset (n=15/17) on brain activation measured by functional MRI.
  
  
  RESULTS
  T-EX significantly improved treadmill-walking velocity by 51% and cardiovascular fitness by 18% (11% and -3% for CON, respectively; P<0.05). T-EX but not CON affected brain activation during paretic, but not during nonparetic limb movement, showing 72% increased activation in posterior cerebellar lobe and 18% in midbrain (P<0.005). Exercise-mediated improvements in walking velocity correlated with increased activation in cerebellum and midbrain.
  
  
  CONCLUSIONS
  T-EX improves walking, fitness and recruits cerebellum-midbrain circuits, likely reflecting neural network plasticity. This neural recruitment is associated with better walking. These findings demonstrate the effectiveness of T-EX rehabilitation in promoting gait recovery of stroke survivors with long-term mobility impairment and provide evidence of neuroplastic mechanisms that could lead to further refinements in these paradigms to improve functional outcomes.
authors.affiliation: Department of General Neurology, University of Maryland, School of Medicine, Baltimore, MD, USA. aluft@jhu.edu
authors.forename: Andreas R
authors.initials: AR
authors.lastname: Luft
authors.forename: Richard F
authors.initials: RF
authors.lastname: Macko
authors.forename: Larry W
authors.initials: LW
authors.lastname: Forrester
authors.forename: Federico
authors.initials: F
authors.lastname: Villagra
authors.forename: Fred
authors.initials: F
authors.lastname: Ivey
authors.forename: John D
authors.initials: JD
authors.lastname: Sorkin
authors.forename: Jill
authors.initials: J
authors.lastname: Whitall
authors.forename: Sandy
authors.initials: S
authors.lastname: McCombe-Waller
authors.forename: Leslie
authors.initials: L
authors.lastname: Katzel
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Goldberg
authors.forename: Daniel F
authors.initials: DF
authors.lastname: Hanley