Alterations in Aerobic Exercise Performance and Gait Economy Following High-Intensity Dynamic Stepping Training in Persons With Subacute Stroke

Background and Purpose: Impairments in metabolic capacity and economy (O(2)cost) 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 O(2)cost. However, particularly in persons with subacute stroke, inconsistent gains in walking function are observed 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 with conventional therapy. Methods: A secondary analysis was performed on data from a randomized controlled trial comparing high-intensity training with conventional interventions, and from the pilot study that formed the basis for the randomized controlled trial. Participants 1 to 6 months poststroke received 40 or fewer sessions of high-intensity variable stepping training (n = 21) or conventional interventions (n = 12). Assessments were performed at baseline (BSL), posttraining, and 2-to 3-month follow-up and included changes in submaximal (V) over dotO(2) (V) over dotO(2submax)) and O(2)cost at fastest possible treadmill speeds and peak speeds at BSL testing. Results: Significant improvements were observed in. (V) over dotO(2submax) with less consistent improvements in O(2)cost, although individual responses varied substantially. Combined changes in both (V) over dotO(2submax) and (V) over dotO(2) (V) over dotO(2) at matched peak BSL speeds revealed stronger correlations to improvements in walking function as compared with either measure alone. Discussion and Conclusions: High-intensity stepping training may elicit significant improvements in (V) over dotO(2submax), whereas changes in both peak capacity and economy better reflect gains in walking function. Providing high-intensity training to improve locomotor and aerobic exercise performance may increase the efficiency of rehabilitation sessions. Video Abstract available for more insights from the authors (see Supplemental Digital Content, http://links.lww.com/JNPT/A142).