Poststroke hemiparesis often leads to a vicious cycle of limited activity, deconditioning, and poor cardiovascular health. Accumulating evidence suggests that exercise intensity is a critical factor determining gains in aerobic capacity, cardiovascular protection, and functional recovery after stroke. High-intensity interval training (HIT) is a strategy that augments exercise intensity using bursts of concentrated effort alternated with recovery periods. However, there was previously no stroke-specific evidence to guide HIT protocol selection.
Purpose: This study aimed to compare within-session exercise responses among three different HIT protocols for persons with chronic (>6 months after) stroke.
Methods: Nineteen ambulatory persons with chronic stroke performed three different 1-d HIT sessions in a randomized order, approximately 1 wk apart. HIT involved repeated 30-s bursts of treadmill walking at maximum tolerated speed, alternated with rest periods. The three HIT protocols were different on the basis of the length of the rest periods, as follows: 30 s (P30), 60 s (P60), or 120 s (P120). Exercise tolerance, oxygen uptake (V˙O2), HR, peak treadmill speed, and step count were measured.
Results: P30 achieved the highest mean V˙O2, HR, and step count but with reduced exercise tolerance and lower treadmill speed than P60 or P120 (P30: 70.9% V˙O2peak, 76.1% HR reserve (HRR), 1619 steps, 1.03 m·s−1; P60: 63.3% V˙O2peak, 63.1% HRR, 1370 steps, 1.13 m·s−1; P120: 47.5% V˙O2peak, 46.3% HRR, 1091 steps, 1.10 m·s−1). P60 achieved treadmill speed and exercise tolerance similar to those in P120, with higher mean V˙O2, HR, and step count.
Conclusions: For treadmill HIT in chronic stroke, a combination of P30 and P60 may optimize aerobic intensity, treadmill speed, and stepping repetition, potentially leading to greater improvements in aerobic capacity and gait outcomes in future studies.
1Department of Rehabilitation Sciences, College of Allied Health Sciences, University of Cincinnati, Cincinnati, OH; 2Departments of Internal Medicine and Cardiology, College of Medicine, University of Cincinnati, Cincinnati, OH; 3Division of Biostatistics and Epidemiology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH; 4Department of Neurology, Physical Medicine and Rehabilitation, College of Medicine, University of Cincinnati, Cincinnati, OH
Address for correspondence: Pierce Boyne, P.T., D.P.T., N.C.S., Department of Rehabilitation Sciences, College of Allied Health Sciences, University of Cincinnati, 3202 Eden Avenue, Cincinnati, OH 45220-0394; E-mail: Pierce.Boyne@uc.edu.
Submitted for publication March 2014.
Accepted for publication June 2014.