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Updated: Mar 28, 2026
Conducting Maximal and Submaximal Endurance Exercise Testing to Measure Physiological and Biological Responses to Acute Exercise in Humans
Published on: October 17, 2018
Submaximal Exercise Testing to Dose High-Intensity Interval Training After Stroke: The FAST Randomized Clinical Trial
Bria L Bartsch1,2, Amanda Engler1,3, Noah Schneider1
1Department of Neurology, University of Kansas Medical Center, Kansas City, KS, USA.
Importance:
High-intensity interval training (HIIT) improves peak oxygen uptake (VO 2 peak) and walking post-stroke. However, previous HIIT trials have primarily implemented maximal exercise testing, limiting clinical implementation.
Objective:
Evaluate the preliminary efficacy of HIIT, compared to moderate-intensity continuous training (MICT) using a submaximal exercise test. Hypothesis: HIIT will produce greater improvements than MICT in VO 2 peak, vascular measures, and walking outcomes.
Design:
This was a randomized preliminary efficacy trial conducted between July 2023 and December 2025.
Setting:
University of Kansas Medical Center.
Participants:
Participants with chronic stroke, 20-85 years of age, were randomized to HIIT or MICT.
Intervention:
HIIT and MICT were performed on a total-body recumbent stepper 3 times per week for 4 weeks, with intensity prescribed using peak power output (PPO) to achieve target heart rate zones derived from a submaximal exercise test. HIIT was performed for 25 minutes with 1-minute vigorous-intensity intervals (65-95% PPO) interspersed with 1-minute active recovery intervals. MICT was performed continuously at 45-65% PPO for 25 minutes.
Main Outcomes:
The primary outcome was change in predicted VO 2 peak. Secondary outcomes included middle cerebral artery velocity, peripheral vascular function, and arterial stiffness with gait speed and walking endurance as tertiary outcomes.
Results:
Forty-nine participants (HIIT: n=25, MICT: n=24) were randomized (62.4(12.5) years, 42.9% female), attended 99.5(2.0)% of sessions, and achieved target intensity zones. No study-related serious adverse events occurred. Our results showed no significant between-group differences (p=0.54) for study outcomes. Both groups significantly improved VO 2 peak (HIIT: +1.13 mL•kg-1•min-1 (95% CI: 0.05-2.21), p=0.04; MICT: +1.58 mL•kg-1•min-1 (95% CI: 0.18-2.97), p=0.03) and with fast gait speed and walking endurance. Peripheral vascular function significantly improved following HIIT.
Conclusions And Relevance:
HIIT can be safely implemented in individuals with chronic stroke using a submaximal exercise test. Both HIIT and MICT elicited clinically meaningful gains in VO2peak and walking. However, only HIIT led to a significant improvement in peripheral vascular function, suggesting a biologic signal for intensity-dependent vascular adaptation.
Trial Registration:
ClinicalTrials.gov identifier: NCT05936008.
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