Abstract
Background Poststroke guidelines recommend moderate-intensity, continuous aerobic training (MCT) to improve aerobic capacity and mobility after stroke. High-intensity interval training (HIT) has been shown to be more effective than MCT among healthy adults and people with heart disease. However, HIT and MCT have not been compared previously among people with stroke.
Objective The purpose of this study was to assess the feasibility and justification for a definitive randomized controlled trial (RCT) comparing HIT and MCT in people with chronic stroke.
Design A preliminary RCT was conducted.
Setting The study was conducted in a cardiovascular stress laboratory and a rehabilitation research laboratory.
Patients Ambulatory people at least 6 months poststroke participated.
Intervention Both groups trained 25 minutes, 3 times per week, for 4 weeks. The HIT strategy involved 30-second bursts at maximum-tolerated treadmill speed alternated with 30- to 60-second rest periods. The MCT strategy involved continuous treadmill walking at 45% to 50% of heart rate reserve.
Measurements Measurements included recruitment and attendance statistics, qualitative HIT acceptability, adverse events, and the following blinded outcome variables: peak oxygen uptake, ventilatory threshold, metabolic cost of gait, fractional utilization, fastest treadmill speed, 10-Meter Walk Test, and Six-Minute Walk Test.
Results During the 8-month recruitment period, 26 participants consented to participate. Eighteen participants were enrolled and randomly assigned to either the HIT group (n=13) or the MCT group (n=5). Eleven out of the 13 HIT group participants attended all sessions. Participants reported that HIT was acceptable and no serious adverse events occurred. Standardized effect size estimates between groups were moderate to very large for most outcome measures. Only 30% of treadmill speed gains in the HIT group translated into overground gait speed improvement.
Limitations The study was not designed to definitively test safety or efficacy.
Conclusions Although further protocol optimization is needed to improve overground translation of treadmill gains, a definitive RCT comparing HIT and MCT appears to be feasible and warranted.
Footnotes
Dr Boyne, Dr Dunning, Dr Carl, Dr Gerson, Mr Rockwell, Ms Westover, Dr McCarthy, and Dr Kissela provided concept/idea/research design. Dr Boyne, Dr Dunning, and Dr McCarthy provided writing. Dr Boyne, Dr Dunning, Dr Carl, Dr Khoury, Mr Rockwell, Ms Keeton, Ms Westover, and Ms Williams provided data collection. Dr Boyne, Dr Dunning, Ms Keeton, and Ms Williams provided data analysis. Dr Boyne, Dr Dunning, Ms Keeton, and Ms Westover provided project management. Dr Boyne, Dr Dunning and Dr Kissela provided fund procurement. Dr Dunning, Ms Keeton, and Dr Kissela provided participants. Dr Dunning, Dr Carl, and Dr Gerson provided facilities/equipment. Dr Dunning and Dr Gerson provided institutional liaisons. Ms Westover provided administrative support. Dr Carl, Dr Gerson, Dr Khoury, Mr Rockwell, Ms Keeton, Ms Westover, Ms Williams, and Dr Kissela provided consultation (including review of manuscript before submission). The authors thank Colleen Meyrose, Renee Jeffreys, Brian Barney, Sarah Buhr, and the staff of the UC Medical Center Cardiovascular Stress Laboratory for their assistance with data collection.
This research was supported by a Magistro Family Research Grant (Dr Dunning), a Promotion of Doctoral Studies Scholarship (Dr Boyne) from the Foundation for Physical Therapy, and an award from the University of Cincinnati Provost's Pilot Research Program (Dr Kissela). Institutional support was provided by an NIH Clinical and Translational Science Award (8UL1-TR000077).
This work was conducted in partial fulfillment of the requirements for Dr Boyne's PhD in Epidemiology in the Department of Environmental Health at the University of Cincinnati College of Medicine.
Portions of this work were presented at the American Physical Therapy Association Combined Sections Meeting, February 2015, Indianapolis, Indiana; the American Heart Association International Stroke Conference, February 2015, Nashville, Tennessee; and the American College of Sports Medicine Annual Conference, May 2015, San Diego, California, and have been accepted for presentation at the IV STEP Conference; July 2016, Columbus, Ohio.
Clinical trial registration: NCT01958606.
- Received May 8, 2015.
- Accepted April 14, 2016.
- © 2016 American Physical Therapy Association
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