Predictors of Improved Aerobic Capacity in Individuals With Chronic Stroke Participating in Cycling Interventions

Abstract

Objective: To determine demographic and physiological factors that predict improvement in aerobic capacity among individuals with chronic stroke participating in cycling interventions.

Design: Secondary analysis of data from 2 randomized clinical trials.

Setting: Research laboratory.

Participants: Individuals with chronic stroke (N=44).

Interventions: Participants were randomized to one of the following interventions: forced aerobic exercise and upper extremity repetitive task practice (FE+UERTP, n=16), voluntary aerobic exercise and upper extremity repetitive task practice (VE+UERTP, n=15), or a nonaerobic control group (control, n=13). All interventions were time-matched and occurred 3 times per week for 8 weeks.

Main outcome measure: Aerobic capacity as measured by peak oxygen consumption per unit time (VO2peak) during maximal cardiopulmonary exercise stress testing.

Results: Significant improvements in VO2peak were observed from baseline to postintervention in the VE+UERTP group (P<.001). Considerable variability was observed among participants relating to postintervention change in VO2peak. Among aerobic exercise participants, a multivariate regression analysis revealed that cycling cadence, baseline VO2peak, and group allocation were significant predictors of change in VO2peak.

Conclusions: High exercise rate (cycling cadence) appears to be an important variable in improving aerobic capacity and should be considered when prescribing aerobic exercise for individuals with chronic stroke. Those with low VO2peak at baseline may benefit the most from aerobic interventions as it relates to cardiorespiratory fitness. Further investigation is warranted to understand the precise role of other exercise and demographic variables in the prescription of aerobic exercise for this population and their effects on secondary stroke prevention and mortality.

Trial registration: ClinicalTrials.gov NCT02076776 NCT02494518.

Keywords: Exercise; Hemiplegia; Rehabilitation; Stroke.

Conflict of interest statement

Conflicts of Interest: Dr. Alberts has authored intellectual property protecting the algorithm associated with the forced exercise bicycle. The remaining authors declare no conflicts of interest.

Copyright © 2019 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Figures

Figure 1 :

Plot depicting percent change in Peak VO2 from baseline to post-intervention among all participants, revealing considerable variability among individuals. Color coding represents average cycling cadence across all exercise sessions or participants who were randomized to the control group (red), revealing that in general, individuals who exercised at a cadence ≥60 revolutions per minute were more likely to demonstrate improved Peak VO2. The aerobic intensity at which each participant exercised (measured as percent of heart rate reserve) for individuals in the FE or VE groups is indicated at the end of each bar. This variable measuring aerobic intensity did not appear to markedly impact change in Peak VO2. Lastly, group assignment to FE or VE is indicated along the x-axis.