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

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.

Conditions

• Chronic Stroke

Interventions

DEVICE

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.

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.

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.

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.

BEHAVIORAL

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.

Sponsors & Collaborators

• The Hong Kong Polytechnic University

  lead OTHER

Principal Investigators

• Shamay NG, PhD · The Hong Kong Polytechnic University

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

SINGLE

Model

PARALLEL

Eligibility

Min Age

50 Years

Max Age

80 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2024-09-01

Primary Completion

2026-12-31

Completion

2026-12-31

Countries

• Hong Kong

Study Locations