title: Potential contributions of training intensity on locomotor performance in individuals with chronic stroke.
abstract: OBJECTIVE
  Many interventions can improve walking ability of individuals with stroke, although the training parameters that maximize recovery are not clear. For example, the contribution of training intensity has not been well established and may contribute to the efficacy of many locomotor interventions. The purpose of this preliminary study was to evaluate the effects of locomotor training intensity on walking outcomes in individuals with gait deficits poststroke.
  
  
  METHODS
  Using a randomized cross-over design, 12 participants with chronic stroke (>6-month duration) performed either high-intensity (70%-80% of heart rate reserve; n = 6) or low-intensity (30%-40% heart rate reserve; n = 6) locomotor training for 12 or fewer sessions over 4 to 5 weeks. Four weeks following completion, the alternate training intervention was performed. Training intensity was manipulated by adding loads or applying resistance during walking, with similar speeds, durations, and amount of stepping practice between conditions.
  
  
  RESULTS
  Greater increases in 6-Minute Walk Test performance were observed following high-intensity training compared with low-intensity training. A significant interaction of intensity and order was also observed for 6-Minute Walk Test and peak treadmill speed, with the largest changes in those who performed high-intensity training first. Moderate correlations were observed between locomotor outcomes and measures of training intensity.
  
  
  CONCLUSIONS
  This study provides the first evidence that the intensity of locomotor practice may be an important independent determinant of walking outcomes poststroke. In the clinical setting, the intensity of locomotor training can be manipulated in many ways, although this represents only 1 parameter to consider.Video Abstract available for more insights from the authors (see Supplemental Digital Content 1, http://links.lww.com/JNPT/A90).
authors.affiliation: Sensory Motor Performance Program (CLH, KSR, AE, TGH), Rehabilitation Institute of Chicago, Chicago, Illinois; Northwestern University Interdepartmental Neuroscience Program (KAL, TGH), Chicago, Illinois; and Department of Physical Therapy and Kinesiology & Nutrition (TGH), University of Illinois at Chicago.
authors.forename: Carey L
authors.initials: CL
authors.lastname: Holleran
authors.forename: Kelly S
authors.initials: KS
authors.lastname: Rodriguez
authors.forename: Anthony
authors.initials: A
authors.lastname: Echauz
authors.forename: Kristan A
authors.initials: KA
authors.lastname: Leech
authors.forename: T George
authors.initials: TG
authors.lastname: Hornby
mesh_terms: D002908:Chronic Disease / Q000534:rehabilitation; D005080:Exercise Test; D005081:Exercise Therapy / Q000379:methods*; D005260:Female; D020233:Gait Disorders, Neurologic / Q000209:etiology / Q000534:rehabilitation*; D006801:Humans; D008297:Male; D008875:Middle Aged; D020521:Stroke / Q000150:complications; D000071939:Stroke Rehabilitation; D016896:Treatment Outcome; D016138:Walking / Q000502:physiology*