Locomotor training intensity after stroke: Effects of interval type and mode

ABSTRACT

Background and Objectives: High-intensity interval training (HIIT) is a promising strategy for improving gait and fitness after stroke, but optimal parameters remain unknown. We tested the effects of short vs long interval type and over-ground vs treadmill mode on training intensity.

Methods: Using a repeated measures design, 10 participants with chronic hemiparesis performed 12 HIIT sessions over 4 weeks, alternating between short and long-interval HIIT sessions. Both protocols included 10 minutes of over-ground HIIT, 20 minutes of treadmill HIIT and another 10 minutes over-ground. Short-interval HIIT involved 30 second bursts at maximum safe speed and 30–60 second rest periods. Long-interval HIIT involved 4-minute bursts at ~90% of peak heart rate (HR_peak) and 3-minute recovery periods at ~70% HR_peak.

Results: Compared with long-interval HIIT, short-interval HIIT had significantly faster mean overground speeds (0.75 vs 0.67 m/s) and treadmill speeds (0.90 vs 0.51 m/s), with similar mean treadmill HR (82.9 vs 81.8%HR_peak) and session perceived exertion (16.3 vs 16.3), but lower overground HR (78.4 vs 81.1%HR_peak) and session step counts (1481 vs 1672). For short-interval HIIT, training speeds and HR were significantly higher on the treadmill vs. overground. For long-interval HIIT, the treadmill elicited HR similar to overground training at significantly slower speeds.

Conclusions: Both short and long-interval HIIT elicit high intensities but emphasize different dosing parameters. From these preliminary findings and previous studies, we hypothesize that overground and treadmill short-interval HIIT could be optimal for improving gait speed and overground long-interval HIIT could be optimal for improving gait endurance.

KEYWORDS:

• Aerobic exercise
• high-intensity interval training
• locomotion
• treadmill
• overground

Acknowledgments

We thank the staff of the University of Cincinnati Medical Center Cardiovascular Stress Laboratory for their assistance with participant screening.

Supplementary Material

Supplemental data for this article can be accessed publisher’s website.

Additional information

Funding

This work was supported by the National Institutes of Health under grants [KL2TR001426, UL1TR001425 and R01HD093694]; and the American Heart Association under grant [17MCPRP33670446]. This content is solely the responsibility of the authors and does not necessarily represent the official views of the funding agencies.