Background and Purpose
Impairments in metabolic capacity and economy (O2cost) are hallmark characteristics of locomotor dysfunction following stroke. High-intensity (aerobic) training has been shown to improve peak oxygen consumption in this population, with fewer reports of changes in O2cost. However, inconsistent gains in walking function are observed, particularly in persons with subacute stroke, with minimal associations with gains in metabolic parameters. The purpose of this study was to evaluate changes in aerobic exercise performance in participants with subacute stroke following high-intensity, variable stepping training as compared to conventional therapy.
Methods
A secondary analysis was performed from a randomized controlled trial (RCT ) comparing high-intensity training to conventional interventions, and a pilot study that formed the basis for the RCT. Participants 1–6 months post-stroke received ≤40 sessions of high intensity variable stepping training (n=21) or conventional interventions (n=12). Assessments were performed at baseline (BSL), post-training and 2–3 month follow-up, and included changes in submaximal VO2 (VO2submax) and O2cost at fastest possible treadmill speeds and peak speeds at BSL testing.
Results
Significant improvements were observed in VO2submax with less consistent decreases in O2cost, although individual responses varied substantially. Combined changes in both VO2submax and VO2 at matched peak BSL speeds revealed stronger correlations to improvements in walking function as compared to either measure alone.
Conclusions
High-intensity stepping training may elicit significant improvements in VO2submax, while changes in both peak capacity and economy better reflect gains in walking function. Providing such training to improve locomotor and aerobic exercise performance may increase the efficiency of rehabilitation sessions. See Video Abstract available for more insights from the authors (see supplemental digital content).