About this trial

Stroke commonly results in persistent leg impairments that limit mobility and reduce quality of life. This study investigates whether combining low-intensity resistance training with blood flow restriction (LIRT-BFR) and transcutaneous electrical nerve stimulation (TENS) can effectively improve leg function in stroke survivors.

Participants with chronic stroke will be randomly assigned to one of four intervention groups: 1) LIRT with simulated BFR and simulated TENS; 2) LIRT with actual BFR and simulated TENS; 3) LIRT with simulated BFR and actual TENS; 4) LIRT with both actual BFR and actual TENS. The resistance training utilizes 20% of each participant's maximum lifting capacity. For blood flow restriction, an automated pressure cuff (SmartCuffs 4.0) will be placed on the upper portion of the affected leg, inflated to 50% of the individual's occlusion pressure during exercises and deflated during rest periods. TENS therapy delivers controlled electrical impulses through electrodes positioned on the anterior thigh.

Each 60-minute session includes a 10-minute warm-up followed by 40 minutes of targeted resistance exercises (leg extensions, leg presses, and weight-bearing squats) and concludes with 10 minutes of stationary cycling. The resistance protocol involves 3 sets of 20 repetitions with standardized rest intervals between sets and exercises. Participants will attend three sessions weekly for six weeks.

Assessments will be conducted at baseline, midpoint (3 weeks), completion (6 weeks), and follow-up (1 month post-intervention). The primary outcome measure is the Fugl-Meyer Assessment for Lower Extremity function, with secondary measures including muscle strength, stiffness, balance, mobility, walking capacity, and gait parameters. To understand the underlying mechanisms, we will measure muscle oxygenation using near-infrared spectroscopy, evaluate muscle structure via ultrasound, and monitor physiological responses including heart rate variability and perceived exertion for safety monitoring.

Eligibility criteria

This trial does not accept healthy volunteers

Qualifiers

are between 50 and 80 years of age;

have had a single stroke more than 6 months and less than 15 years;

have at least 5 degrees of active ankle dorsiflexion in the antigravity position;

are able to walk 10 m independently, with or without a walking aid;

Disqualifiers

presence of other comorbidities like varicose veins, peripheral neuropathy, cancer, musculoskeletal injury, lower limb peripheral edema, post-surgical swelling, open wounds, or on a medication that increases blood clotting risk;

resting blood pressure ≥ 160/100 mmHg even after taking medications, cardiovascular comorbidity, heart failure, unstable angina, by-pass surgery, a pacemaker;

administration of botulinum toxin in the lower limb at least 6 months prior to training;

history of epilepsy, cochlear implants, any type of deep brain stimulator and metal implants in the head or neck;

Trial design

Design model

Parallel

Treatments tested in this trial

Blood flow restriction (BFR)
Device
BFR implementation involves an automated restriction band (SmartCuffs 4.0) positioned at the proximal region of the affected lower extremity, calibrated to 50% of the individual's lower limb occlusion pressure (LOP). The pressure system remains inflated throughout active training phases and is systematically deflated during inter-exercise intervals.
Transcutaneous electrical nerve stimulation (TENS)
Device
TENS will be delivered to the anterior thigh region of the paretic leg using a 120z Dual-Channel TENS Unit (ITO Physiotherapy \& Rehabilittaion, Co, Ltd, Tokyo, Japan). The TENS stimulation will be at 100 Hz, with 0.2 ms square pulses at an intensity of twice the sensory threshold (defined as the minimum intensity at which subject reported feeling a tingling sensation and below the motor threshold as indicated by the absence of muscle twitching.
Sham blood flow restriction (Sham-BFR)
Device
Sham BFR implementation involves an automated restriction band (SmartCuffs 4.0) positioned at the proximal region of the affected lower extremity, calibrated to 50% of the individual's lower limb occlusion pressure (LOP). But the pressure system remains deflated throughout active training and resting phases.
Sham transcutaneous electrical nerve stimulation (Sham-TENS)
Device
Sham TENS will be delivered to the anterior thigh region of the paretic leg using a 120z Dual-Channel TENS Unit (ITO Physiotherapy \& Rehabilittaion, Co, Ltd, Tokyo, Japan). The TENS stimulation will be at 100 Hz, with 0.2 ms square pulses at an intensity of twice the sensory threshold (defined as the minimum intensity at which subject reported feeling a tingling sensation and below the motor threshold as indicated by the absence of muscle twitching. But the stimulator will only be applied for the first and last 30 seconds.
Low-intensity resistance training (LIRT)
Behavioral
The LIRT protocol utilizes 20% of one-repetition maximum (1-RM) as the standardized training load. LIRT including leg extensions, leg presses, and load-bearing squats focused on the affected limb. Each resistance exercise consists of 3 sets of 20 repetitions with rest intervals.

Treatment groups

60 Participants

are divided into 4 treatment groups

Group A: LIRT + BFR + TENSExperimental treatment 3 interventions

Group B: LIRT + sham BFR + TENSSham comparator 3 interventions

Group C: LIRT + BFR + sham TENSSham comparator 3 interventions

Group D: LIRT + sham BFR + sham TENSPlacebo comparator 3 interventions

Trial outcomes

Primary outcomes

1

Fugl-Meyer Assessment of Lower Extremity (FMA-LE)

FMA-LE is used to evaluate the lower extremity motor control, including reflexes, voluntary control of isolated movement and coordination. The scale score ranging from 0 to 34, with 17 items and ordinal scoring from 0 to 2. A higher score indicates a better lower extremity motor control.

Time frame