Does priming the brain with aerobic exercise increase arm recovery from a stroke rehabilitation program?

This study is a randomised, 3-arm parallel adaptive trial assessing the feasibility, safety, and tolerability of two aerobic exercise primers of high-intensity interval training (HIIT) and moderate intensity training (MIT) prior to high-dose bootcamp rehabilitation in individuals with stroke. All participants will engage in high-dose bootcamp rehabilitation; only the aerobic exercise priming paradigm will vary across individuals. Aerobic Exercise Priming (Arm 1 & 2): Participants randomised into Arms 1 and 2 will be required to complete an aerobic exercise priming session on a recumbent exercise bike, approximately 30 minutes before their scheduled bootcamp rehabilitation session. This will be delivered in groups of up to 2-3. Individual prescription of exercise intensity will be determined using rate of perceived exertion (RPE) and heart rate (HR) response obtained from exercise testing (performed at enrolment as screening criteria). Participants will be required to complete three aerobic exercise priming sessions per week over the 5-week program duration. Arm 1: HIIT priming • Six blocks of 40 seconds of high-intensity intervals (RPE 14–16 or 70–85% HRR) with six blocks of 20 seconds of active recovery (RPE 10-11 or 20-35% HRR). • 5-minute warm-up and cool-down period of passive cycling at a low intensity of 10-25W Arm 2: MIT priming • 20 minutes of moderate-intensity continuous aerobic exercise (40-59% HRR or RPE 12-13/20). All exercise sessions will be supervised by the main researcher. Adherence to aerobic exercise priming sessions will be recorded. High-dose Boot Camp Rehabilitation: Every participant in the trial will complete an upper-limb sensorimotor rehabilitation program designed to address identified impairments and improve upper-limb function. Programs will be individually tailored based on initial assessments and rehabilitation goals. All participants will be required to complete a 5-week program delivering 3h per day, 5 days per week (total of 75h) comprising: 1) An upper-limb group exercise class (ratio 4:1), 2) Rehabilitation technologies (for example, robotics, virtual reality, EEG EMG biofeedback, non-immersive gaming, functional electrical stimulation and interactive multisensory gaming technologies, 3) task-specific training (1:1), 4) A home exercise program based on the Graded Repetitive Arm Supplementary Program (GRASP) or pre-recorded videos such as Different Strokes UK YouTube (informed by impairment level and patient preference). The GRASP program includes written and video guides to perform a range of exercises at home that include: stretching, arm strengthening, hand strengthening, coordination, and hand skills. The Different Strokes UK YouTube channel involves step-by-step videos to perform exercises that focus on mobility and movement, strength, core and range of motion. The 18h per week will be achieved by 13h delivered in person (based on tasks above) and 5h of home exercises (1h per weekday, recorded in an activity log). Adherence to both in-person and at-home will be recorded. Each 5-week program will have a maximum of 5 patients. A Physiotherapist will deliver all rehabilitation sessions. The adaptive element of this feasibility trial includes an interim analysis to assess whether arms may need to be discontinued if they meet any of the pre-defined feasibility and safety termination threshold criteria below: Serious adverse event: more than 20% of participants experience SAE related to exercise intervention. Adherence to exercise priming intervention: less than 50% of participants complete prescribed exercise sessions. Adherence to rehabilitation protocol: less than 50% complete rehabilitation sessions. Dropout rate: more than 50% withdraw from the arm. Acceptability: more than 50% rate the intervention as disagree or strongly disagree to being acceptable (5-point Likert scale). An interim analysis will be performed after 33% and 66% of data collection is completed. If an intervention arm is dropped due to meeting pre-defined stop criteria, randomisation ratios will be adjusted accordingly.