Power Exercise for Stroke Recovery: The POWER Pilot Trial (POWER-P)

Power Exercise for Stroke Recovery: A Pilot Randomized Controlled Trial (POWER-Pilot)

Weakness is one of the most common consequences of stroke. For the over 750,000 Canadians living with stroke, many daily activities like standing from a chair, walking and balance not only require strength but often efforts in bursts, known as muscle power. Strength training can improve muscle strength and, when performed at higher speeds, can help build muscle power. Current guidelines for stroke recommend strength training but these are commonly performed at lower intensities and do not include any focus on building muscle power. There has been very little research on power training after stroke.

A 10-week power training program for people living with stroke, Power Exercise for Stroke Recovery (POWER-Feasibility, NCT05816811) was recently evaluated. POWER includes 3 phases of progressive exercise: building familiarity with the upper and lower body exercises, then strength, and lastly muscle power. The results from POWER-Feasibility are promising, suggesting that POWER is safe and may improve stroke recovery. POWER-Feasibility was a small study (15 participants), and POWER was not compared to a control intervention.

A pilot randomized controlled trial of POWER (POWER-Pilot) will now be conducted. Sixty people who are at least 6 months after stroke will be recruited. They will be randomly assigned to participate in POWER or standard strength training for stroke at lower intensities and without focus on power training. The feasibility of a randomized study will be examined, and whether POWER can improve walking, strength and balance compared to the control group. Results from POWER-Pilot will help design a larger randomized trial in the future (POWER-RCT), and may ultimately be important for stroke rehabilitation teams to better understand whether power training can help people recovering from stroke.

With the population aging, nearly 750,000 Canadians live with stroke, surpassing previous projections by 15 years. Post-stroke deficits, including loss of strength, balance and walking ability, are highly common. Sarcopenia, often associated with aging yet highly prevalent in stroke, underlie these deficits and contribute to lower discharge rates after hospitalization.

Community stroke exercise programs can improve strength and function to aid in recovery beyond hospital care. Most programs however follow conservative resistance exercise training (RET) approaches, as stroke guidelines are based on limited evidence. Unlike benefits of RET shown in mobility in older adults, stroke trials have shown large improvements in strength without concurrent changes in mobility, motor function or walking.

Power-focused RET involves moving lighter weights at high speed to develop muscle power, which may be more important than strength alone for activities critical for independent living such as climbing stairs, balance, and walking speed. A novel, progressive power training-focused community program for stroke (Power Exercise for Stroke Recovery, POWER) was developed to influence recovery of physical function. Following a successful single-group feasibility study of POWER (POWER-Feasibility, NCT05816811), a phase II pilot randomized trial (POWER-Pilot) is needed.

This pilot randomized trial aims to answer the following questions: 1) What is the feasibility of a multi-site randomized design to evaluate Power Exercise for Stroke Recovery (POWER), a power-focused training program for people living in the community with stroke? 2) What are the preliminary estimates of the effect of POWER compared to conventionally recommended RET (Strength Training Engaging Guidelines to Enhance Total Health, STRENGTH) for people living in the community with stroke on outcomes of functional mobility (walking, balance), post-stroke fatigue, psychological wellbeing, cognition, and health-related quality of life?

Sixty participants (6 months post-stroke, completed rehabilitation) will be randomized to POWER or STRENGTH. POWER involves 3 progressive phases: 1) Familiarization (1 week), 2) Strength (4 weeks, 2-3 sets, 5-8 repetitions), and 3) Power (5 weeks, 2-3 sets, 15-20 repetitions, fast tempo). STRENGTH is based on current RET clinical practice guidelines for stroke with no focus on power. POWER and STRENGTH matched in length, frequency (3x/week) and format (in-person supervision) but differentiated by approach to exercise progression, intensity, and tempo.

Feasibility indicators such as randomization and blinding have predefined success and progression thresholds. Estimates of the effect of POWER include functional mobility (Timed Up and Go, primary clinical outcome), walking speed, post-stroke fatigue, psychological well-being, cognition, balance, and quality of life, and will be assessed pre-post, and at 8-week follow-up. Sex and gender-related factors associated with feasibility and changes in clinical outcomes as social determinants of exercise participation post-stroke will also be examined.

Feasibility outcomes and effect estimates from POWER-Pilot will guide scalability for a fully powered RCT and future cost-effectiveness evaluation, shaping exercise best practices and facilitating hospital-to-community transition through broader implementation in community programs.

Inclusion Criteria:

1. ≥19 years old
2. ≥6 months poststroke,
3. able to walk >10 meters with or without an assistive device
4. have mild to moderate stroke severity (modified Rankin Scale ≤3)
5. without significant cognitive impairment that would preclude safe exercise, screened via Montreal Cognitive Assessment-Blind score <18

Exclusion Criteria:

1. Any contraindications to exercise for people with cardiovascular disease, such as unstable angina, uncontrolled hypertension, orthostatic blood pressure with exercise, or uncontrolled arrhythmias or
2. Actively engaged in or have made plans to engage in stroke rehabilitation services