# High-intensity interval training with robot-assisted gait therapy vs. treadmill gait therapy in chronic stroke: a randomized controlled trial PMID: 40753404 Journal: Journal of neuroengineering and rehabilitation Published: 2025-08-02 Authors: Kim J, Do J, Bae CR, Mo YH, Kim JH, Kim DY ## Question Does combining HIIT with robot-assisted gait therapy improve gait, balance, lower-limb function, cardiopulmonary function, activities of daily living, and body composition more than treadmill-based gait therapy in patients with chronic stroke? ## Summary This exploratory randomized controlled trial compared HIIT integrated into robot-assisted gait therapy with treadmill-based gait therapy in adults with chronic stroke and dependent ambulation. Both groups trained for 30 minutes, three times weekly for 8 weeks. The robot-HIIT protocol alternated 2 minutes at moderate perceived exertion with 3 minutes at high perceived exertion, using an end-effector robot and continuous heart-rate monitoring. Forty-four of 48 randomized participants completed outcome assessments. The robot-HIIT group improved more than treadmill therapy on walking speed, ambulation category, balance, walking endurance, and lower-limb motor function, while VO2max improved within the robot-HIIT group but did not differ significantly between groups. The findings are promising for stroke rehabilitation but are not directly generalizable to unsupervised consumer HIIT. ## Population - Adults with chronic hemorrhagic or ischemic stroke, gait disturbance, FAC score 3 or less, and more than 6 months post-stroke. - Sample size: 48 - Age: Control 64.0 +/- 10.2 years; robot-HIIT 59.22 +/- 14.0 years. - Sex: Control 11 male/11 female; robot-HIIT 16 male/6 female. - Fitness level: Dependent ambulation after chronic stroke; FAC 3 or less. - Health status: Chronic stroke patients with gait disturbance; uncontrolled cardiovascular or physical conditions preventing high-intensity training were excluded. ## Methodology - Prospective randomized controlled trial without blinding. - 8 weeks - Tertiary hospital outpatient rehabilitation medicine clinic in South Korea. - Randomized and controlled study design. ## Protocol - RAGT with HIIT. - Modality: End-effector robot-assisted gait therapy using Morning Walk. - Work intervals: 3 minutes high intensity. - Recovery: 2 minutes moderate intensity. - Sets or repetitions: Repeated moderate/high cycles during a 30-minute session. - Intensity: Moderate RPE 10-12 and high RPE > 14; target heart rate calculated using heart-rate reserve. - Session duration: 30 minutes. - Frequency: 3 sessions/week. - Program length: 8 weeks. - Progression: Individualized mode and cadence adjustments; cadence 30-70 steps/min. - Treadmill gait therapy. - Modality: Treadmill-based gait therapy. - Intensity: Borg RPE 13-15; speed gradually increased over time. - Session duration: 30 minutes. - Frequency: 3 sessions/week. - Program length: 8 weeks. - Progression: Treadmill speed gradually increased over time while therapist monitored heart rate to maintain target intensity. ## Outcomes ### 10-meter walk test Status: improved The primary outcome improved significantly more in robot-HIIT than treadmill control; robot-HIIT changed from 0.41 +/- 0.23 to 0.55 +/- 0.29 m/s while control changed from 0.50 +/- 0.22 to 0.52 +/- 0.24 m/s. Between-group change 0.14 +/- 0.13 vs 0.01 +/- 0.08; p < 0.001; d = 1.2; CI [0.065, 0.198]. ### Functional Ambulation Category Status: improved Both groups improved, with greater improvement in robot-HIIT. Control 2.72 +/- 0.63 to 3.59 +/- 1.00; robot-HIIT 2.40 +/- 0.73 to 3.81 +/- 1.36; between-group p = 0.009; d = 0.79 reported for change comparison. ### Balance and lower-limb motor function Status: improved BBS and FMA-LE improved in both groups and improved more in robot-HIIT. BBS between-group p = 0.012 in table and p = 0.015 in abstract; FMA-LE between-group p < 0.001; FMA-LE change d = 1.27. ### 2-minute walk test Status: improved Only robot-HIIT showed a significant within-group improvement in 2MWT, and between-group difference favored robot-HIIT. Control 68.22 +/- 32.29 to 72.59 +/- 34.16 m; robot-HIIT 56.81 +/- 38.25 to 74.50 +/- 42.27 m; between-group p = 0.008 in table and p = 0.005 in abstract. ### VO2max Status: mixed VO2max improved significantly within robot-HIIT, but the between-group difference was not significant. Robot-HIIT 13.50 +/- 9.31 to 20.74 +/- 9.03 ml/kg/min; control 21.59 +/- 10.26 to 25.69 +/- 14.76 ml/kg/min; between-group p = 0.901. ### Modified Barthel Index and lean body mass Status: mixed MBI improved within the control group only and did not differ significantly between groups; lean body mass did not significantly change or differ between groups. MBI between-group p = 0.473; lean body mass between-group p = 0.613. ## Practical Insights - In clinical populations with neurological impairment, RPE may be necessary alongside heart-rate targets because medications, spasticity, weakness, and fatigue can distort heart-rate based intensity monitoring. - Standard interval durations can be paired with individualized cadence and modality selection to hit intensity targets. - Clinical HIIT findings involving robotics and therapist supervision should not be generalized to consumer bodyweight HIIT without strong caveats. - For chronic stroke rehabilitation, combining task-specific gait practice with high-intensity intervals may be more promising than treadmill gait therapy alone. ## Limitations - Small exploratory sample. - No blinding and potential observer bias. - Single tertiary hospital in South Korea. - Chronic stroke-only sample limits generalization to acute or subacute stroke. - Baseline lower-limb function differed between groups because allocation was not stratified. - Mechanisms were not directly studied. - No RAGT-alone or HIIT-alone group, so independent effects cannot be isolated. - Only one standardized HIIT protocol was tested. - Adverse-event reporting was not explicit in the extracted main text. ## Safety And Adherence - The extracted main text did not report explicit adverse-event counts or injury events. - Patients with uncontrolled cardiovascular or other physical conditions preventing high-intensity gait training were excluded. - Continuous heart-rate monitoring, therapist presence, RPE adjustment, and robot body-weight support were used during intervention sessions. ## Original Sources - [PubMed](https://pubmed.ncbi.nlm.nih.gov/40753404/) (pubmed) - [DOI](https://doi.org/10.1186/s12984-025-01674-0) (doi) - [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12317475/) (full text) ## Agent Guidance Preserve the paper-level scope of this note. Do not generalize beyond the population, protocol, measured outcomes, and limitations above.