Blood Flow Restriction and Transcutaneous Electrical Nerve Stimulation on Motor Function in Stroke

NCT ID: NCT06973590

Last Updated: 2025-05-15

Basic Information

• Recruitment Status: RECRUITING
• Clinical Phase: NA
• Total Enrollment: 80 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2024-09-01
• Study Completion Date: 2026-12-31

Brief Summary

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.

Detailed Description

Stroke often leads to persistent lower-limb impairments, limiting functional recovery and quality of life. Low-intensity resistance training with blood flow restriction (LIRT-BFR) has shown promise in improving muscle function in healthy populations, but its effects in stroke rehabilitation remain underexplored. Additionally, while BFR and electrical stimulation have been beneficial for pain relief and muscle activation, the impact of combining BFR with transcutaneous electrical nerve stimulation (TENS) in stroke patients remains unknown. The objectives of this study is to evaluate whether a multi-mode exercise rehabilitation training program of LIRT-BFR and TENS can restore lower extremity strength, mobility, and quality of life.

In this randomized controlled trial, chronic stroke patients will be allocated to one of four groups: 1) LIRT + sham BFR + sham TENS, 2) LIRT + BFR + sham TENS, 3) LIRT + sham BFR + TENS, and 4) LIRT + BFR + TENS. The LIRT protocol utilizes 20% of one-repetition maximum (1-RM) as the standardized training load. 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. TENS application targets the anterior thigh region.

The intervention protocol comprises a structured 60-minute session beginning with a 10-minute preparatory warm-up, followed by 40 minutes of targeted resistance exercises including leg extensions, leg presses, and load-bearing squats focused on the affected limb, concluding with 10 minutes of aerobic cycling. Each resistance exercise consists of 3 sets of 20 repetitions with rest intervals. The assessments will be conducted at baseline, mid-intervention (3 weeks), post-intervention (6 weeks), and follow-up (1 month post-completion).

The primary outcome measure will be the Fugl-Meyer Assessment Lower Extremity (FMA-LE) score, and secondary outcome measures including muscle strength, stiffness, balance, functional mobility, walking capacity, gait speed, etc. To elucidate the underlying mechanisms, the study will use near-infrared spectroscopy (NIRS) to assess muscle oxygenation and hemodynamics, ultrasound for muscle morphology, and exercise measures like heart rate variability (HRV) and rating of perceived exertion (RPE) for safety consideration.

Conditions

Chronic Stroke

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: SINGLE

Study Groups

LIRT + BFR + TENS

All subjects will receive 60-minute sessions of LIRT with both actual BFR and actual TENS intervention, 3 sessions per week for 6 weeks.

Group Type: EXPERIMENTAL

Blood flow restriction (BFR)

Intervention Type: 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)

Intervention Type: 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.

Low-intensity resistance training (LIRT)

Intervention Type: 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.

LIRT + sham BFR + TENS

All subjects will receive 60-minute sessions of LIRT with simulated BFR and actual TENS, 3 sessions per week for 6 weeks.

Group Type: SHAM_COMPARATOR

Transcutaneous electrical nerve stimulation (TENS)

Intervention Type: 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)

Intervention Type: 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.

Low-intensity resistance training (LIRT)

Intervention Type: 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.

LIRT + BFR + sham TENS

All subjects will receive 60-minute sessions of LIRT with actual BFR and simulated TENS, 3 sessions per week for 6 weeks.

Group Type: SHAM_COMPARATOR

Blood flow restriction (BFR)

Intervention Type: 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.

Sham transcutaneous electrical nerve stimulation (Sham-TENS)

Intervention Type: 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)

Intervention Type: 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.

LIRT + sham BFR + sham TENS

All subjects will receive 60-minute sessions of LIRT with simulated BFR and simulated TENS, 3 sessions per week for 6 weeks.

Group Type: PLACEBO_COMPARATOR

Sham blood flow restriction (Sham-BFR)

Intervention Type: 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)

Intervention Type: 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)

Intervention Type: 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.

Interventions

Blood flow restriction (BFR)

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.

Intervention Type: DEVICE

Transcutaneous electrical nerve stimulation (TENS)

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.

Intervention Type: DEVICE

Sham blood flow restriction (Sham-BFR)

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.

Intervention Type: DEVICE

Sham transcutaneous electrical nerve stimulation (Sham-TENS)

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.

Intervention Type: DEVICE

Low-intensity resistance training (LIRT)

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.

Intervention Type: BEHAVIORAL

Eligibility Criteria

Inclusion Criteria

1. are between 50 and 80 years of age;

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

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

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

5. are able to score 6 or higher out of 10 on the abbreviated mental test;

6. have no skin allergies (e.g. redness or itchiness after application of the electrical stimulation pads) to electrical stimulation or electrodes;

7. are able to follow instructions and give informed consent.

Exclusion Criteria

1. 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;

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

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

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

5. currently not participating in resistance training or high-intensity or long duration cardiovascular exercise;

6. lack the ability to feel pain (because of paralysis), or other subjects who cannot complain of discomfort.

• Minimum Eligible Age: 50 Years
• Maximum Eligible Age: 80 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

The Hong Kong Polytechnic University

OTHER

Sponsor Role: lead

Responsible Party

Shamay Ng

Prof.

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Shamay NG, PhD

Role: PRINCIPAL_INVESTIGATOR

The Hong Kong Polytechnic University

Locations

The Hong Kong Polytechnic University

Hong Kong, , Hong Kong

Site Status: RECRUITING

Countries

Hong Kong

Central Contacts

Shamay NG, PhD

Role: CONTACT

shamay.ng@polyu.edu.hk

+852 27664889

Facility Contacts

Shamay NG, PhD

Role: primary

shamay.ng@polyu.edu.hk

+852 27664889

Other Identifiers

2025_BFR+TENS_STROKE

Identifier Type: -

Identifier Source: org_study_id