# Effect of High-Intensity Interval Training and Moderate-Intensity Continuous Training in People With Poststroke Gait Dysfunction: A Randomized Clinical Trial PMID: 37947080 Journal: Journal of the American Heart Association Published: 2023-11-21 Authors: Marzolini S, Robertson AD, MacIntosh BJ, Corbett D, Anderson ND, Brooks D, Koblinsky N, Oh P ## Question Do conventional moderate-intensity continuous training and a novel high-intensity interval training program have different effects on peak oxygen uptake and 6-minute walk distance in people with poststroke gait dysfunction? ## Summary In a 24-week randomized trial of 47 people with poststroke gait dysfunction, replacing three of five weekly moderate continuous walking sessions with high-intensity interval treadmill sessions produced a larger improvement in peak oxygen uptake than continuing five weekly moderate continuous sessions. Both groups improved 6-minute walk distance similarly. The HIIT program was delivered in a screened rehabilitation setting with treadmill harness support, heart-rate monitoring, supervised sessions, and a four-week preparatory phase. ## Population - Forty-seven people with poststroke gait dysfunction randomized to HIIT plus MICT or MICT in a rehabilitation program. - Sample size: 47 - Age: Mean 62 +/- 11 years overall; group ranges 34-85 and 38-77 years - Sex: 81% men overall - Fitness level: Low cardiorespiratory fitness, about 60% of predicted peak oxygen uptake norms at baseline - Health status: Poststroke gait dysfunction with cardiovascular risk comorbidities common ## Methodology - 24-week, two-arm, parallel-group superiority randomized clinical trial - 24 weeks - Toronto Rehab Cardiovascular Prevention and Rehabilitation program in Toronto, Canada, with mostly supervised treadmill training and some home/community walking - Randomized and controlled study design. ## Protocol - HIIT plus MICT. - Modality: Mostly treadmill walking with harness and handrail support; occasional overground walking. - Work intervals: 30 seconds in workout 1; 2 minutes in workout 2. - Recovery: 60 seconds active recovery in workout 1; 3 minutes active recovery in workout 2. - Sets or repetitions: Workout 1 progressed from 3 to 15 intervals; workout 2 interval count not specified in full text. - Intensity: Maximal safe/tolerable treadmill speed and grade, guided by RPE >=17, >=91% peak oxygen uptake workload/heart rate, and above ventilatory threshold. - Session duration: Approximately 20-22 minutes plus 5-minute warmup and 5-minute cooldown. - Frequency: 3 HIIT sessions/week plus 2 MICT sessions/week during weeks 5-24. - Program length: 24 weeks total, with 20 weeks of HIIT after a 4-week preparatory phase. - Progression: Initial 4-week foundation; workout 1 progressed from 3 to 15 intervals; treadmill speed/grade reassessed every 3 weeks and after 12-week CPET. - MICT. - Modality: Mostly treadmill or overground walking. - Work intervals: Continuous walking. - Intensity: Ventilatory anaerobic threshold from CPET; if unavailable, 60%-80% heart-rate reserve or peak oxygen uptake plus Borg RPE 12-16. - Session duration: Progression toward a maximum of 60 minutes plus 3-minute warmup and cooldown. - Frequency: 5 sessions/week. - Program length: 24 weeks. - Progression: Initial prescription up to 1.6 km depending on tolerance; progressed about every 2 weeks by increasing distance, then intensity, then distance; adjusted after 12-week CPET. ## Outcomes ### Peak oxygen uptake Status: improved HIIT improved peak oxygen uptake more than MICT: 5.7 +/- 3.1 versus 2.4 +/- 2.7 mL/kg/min, a relative change of 30 +/- 18% versus 13 +/- 15%. Adjusted mean difference 3.2 mL/kg/min, 95% CI 1.5 to 4.8, P < 0.001, partial eta squared 0.212 ### 6-minute walk distance Status: no clear change Both groups improved, but between-group difference was not significant: HIIT 83.4 +/- 53.6 m versus MICT 70.9 +/- 44.3 m. Mean difference 12.5 m, 95% CI -17 to 42, P = 0.401, partial eta squared 0.005 ### Ventilatory anaerobic threshold oxygen uptake Status: improved HIIT produced a greater increase than MICT. Mean difference 2.07 mL/kg/min, 95% CI 0.59 to 3.6, P = 0.008, partial eta squared 0.197 ### Secondary outcomes Status: no clear change No other significant between-group differences were observed across gait speed, gait economy, cognition, balance, stair climb, strength, and quality of life. ### Safety Status: mixed No study-related serious adverse events occurred; adverse events occurred in both groups and severe events were not intervention-related. 33 AEs in 23 participants; HIIT 16 AEs in 10/24 participants, MICT 17 AEs in 13/23 participants ## Practical Insights - In screened poststroke rehabilitation, adding three weekly HIIT sessions to a five-session weekly aerobic program can produce greater CRF gains than all-MICT training. - Functional walking gains may not track directly with CRF gains; MICT at ventilatory threshold produced similar 6MWD improvement. - Clinical HIIT protocols may require a foundation phase, objective intensity testing, fall protection, and active monitoring. - A combination of short 30-second intervals and longer 2-minute intervals is feasible in a supervised treadmill setting. ## Limitations - Single-center trial - Small sample and stopped before revised recruitment target because of COVID-19 restrictions - 6MWD and secondary outcome assessors were not blinded - Clinical poststroke population and supervised treadmill/harness setting limit consumer generalizability - Full-text extraction did not use supplemental protocol tables ## Safety And Adherence - No study-related serious adverse events. - Adverse events were queried at each visit and graded with Common Terminology Criteria for Adverse Events. - Harness support, handrail support, and supervised heart-rate monitoring were part of the delivery context. - Severe adverse events included bowel bleed, falls, orthostatic hypotension, gall bladder surgery, and kidney stones, all reported as not intervention-related. ## Original Sources - [PubMed](https://pubmed.ncbi.nlm.nih.gov/37947080/) (pubmed) - [DOI](https://doi.org/10.1161/JAHA.123.031532) (doi) - [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10727274/) (full text) ## Agent Guidance Preserve the paper-level scope of this note. Do not generalize beyond the population, protocol, measured outcomes, and limitations above.