Effects of Low-Load Blood Flow Restriction Exercise on Rectus Femoris Muscle Morphology in Individuals With Relapsing-Remitting Multiple Sclerosis (RRMS-BFR)

June 9, 2026 updated by: Hanifi Bal

Effects of Low-Load Blood Flow Restriction Exercise on Rectus Femoris Muscle Morphology in Individuals With Relapsing-Remitting Multiple Sclerosis: A Three-Arm Randomized Controlled Trial

Multiple sclerosis (MS) is a chronic neurological disease associated with reduced muscle strength, impaired mobility, increased fatigue, and deterioration in muscle morphology. Rectus femoris muscle atrophy and reduced muscle quality have been linked to functional limitations and decreased mobility in individuals with MS.

Blood flow restriction (BFR) training is a rehabilitation strategy that combines low-load exercise with partial vascular occlusion, enabling muscular adaptations comparable to those achieved with higher exercise loads. Although BFR has demonstrated promising results in several clinical populations, evidence regarding its effects on muscle morphology in individuals with relapsing-remitting multiple sclerosis (RRMS) remains limited.

The purpose of this randomized controlled trial is to investigate the effects of low-load BFR exercise on rectus femoris muscle morphology in individuals with RRMS. Thirty participants with RRMS (EDSS 2.5-3.5) will be randomly assigned to one of three groups: a BFR exercise group, a sham-BFR exercise group, or an exercise-only control group. All participants will complete the same supervised exercise program twice weekly for eight weeks.

The primary outcome will be rectus femoris muscle thickness assessed by ultrasonography. Secondary outcomes will include rectus femoris echo intensity, knee extensor muscle strength, Timed 25-Foot Walk performance, Nine-Hole Peg Test performance, Symbol Digit Modalities Test scores, and Modified Fatigue Impact Scale scores.

This study aims to determine whether the addition of blood flow restriction to a standardized low-load exercise program results in superior morphological and functional adaptations compared with sham-BFR and exercise-only conditions in individuals with RRMS.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Multiple sclerosis (MS) is a chronic inflammatory and neurodegenerative disease of the central nervous system characterized by demyelination, axonal degeneration, and progressive functional impairment. Individuals with relapsing-remitting multiple sclerosis (RRMS) frequently experience reductions in lower-extremity muscle strength, impaired walking performance, fatigue, and decreased physical function. Among lower-extremity muscles, the rectus femoris (RF) plays a critical role in knee extension, gait performance, and functional mobility. Previous studies have demonstrated associations between RF muscle morphology, muscle performance, and mobility outcomes in individuals with MS.

Blood flow restriction (BFR) exercise involves the application of external pressure to the proximal portion of a limb during low-load exercise. By partially restricting arterial inflow and substantially reducing venous return, BFR creates a hypoxic and metabolically stressful environment within the exercising muscle. This physiological stimulus promotes early recruitment of fast-twitch motor units and may enhance anabolic signaling pathways despite the use of relatively low exercise loads. Consequently, BFR has emerged as a promising rehabilitation strategy for populations that may not tolerate high-intensity resistance training.

Although preliminary evidence suggests that BFR is feasible and safe in people with MS, existing studies have primarily focused on functional outcomes, and the effects of BFR on muscle morphology remain unclear. Furthermore, no randomized controlled trial has investigated rectus femoris muscle morphology as a primary outcome using a three-arm design incorporating both sham-BFR and exercise-only control conditions.

This study is designed as a prospective, parallel-group, three-arm randomized controlled trial. Thirty individuals with RRMS aged 18-65 years and an Expanded Disability Status Scale (EDSS) score between 2.5 and 3.5 will be recruited. Participants will be randomly allocated in a 1:1:1 ratio to one of three groups:

  1. Low-load exercise with blood flow restriction (BFR).
  2. Low-load exercise with sham blood flow restriction.
  3. Low-load exercise without blood flow restriction (control).

All groups will participate in an identical supervised exercise program twice weekly for eight weeks (16 sessions total). Exercise sessions will include a standardized warm-up period, quadriceps-focused strengthening exercises, cycling exercise, and cool-down/stretching activities. The only systematic difference between groups will be the cuff condition applied during the strengthening component.

In the BFR group, individualized arterial occlusion pressure (AOP) will be determined using a pneumatic cuff system, and exercise will be performed at 50-60% of AOP. In the sham-BFR group, cuffs will be applied in the same location but inflated to a pressure insufficient to produce meaningful vascular occlusion. The control group will perform the same exercise program without cuff application.

Outcome assessments will be conducted at baseline and after completion of the intervention. The primary outcome will be rectus femoris muscle thickness measured by ultrasonography. Secondary outcomes will include rectus femoris echo intensity, knee extensor muscle strength, Timed 25-Foot Walk performance, Nine-Hole Peg Test performance, Symbol Digit Modalities Test scores, and Modified Fatigue Impact Scale scores.

The study is expected to provide novel evidence regarding the effectiveness of low-load BFR exercise for improving muscle morphology and related functional outcomes in individuals with RRMS. In addition, the inclusion of a sham-BFR condition will allow differentiation between the physiological effects of blood flow restriction and potential placebo or expectancy effects associated with cuff application.

Study Type

Interventional

Enrollment (Estimated)

30

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:* Age 18-65 years

  • Diagnosis of relapsing-remitting multiple sclerosis according to revised McDonald criteria
  • EDSS score between 2.5 and 3.5
  • Clinically stable disease
  • No relapse within the previous 3 months
  • No corticosteroid treatment within the previous 3 months
  • Ability to participate in exercise training
  • Written informed consent

Exclusion Criteria:* Deep vein thrombosis or pulmonary embolism history

  • Peripheral vascular disease
  • Uncontrolled hypertension
  • Severe cardiovascular disease
  • Pregnancy
  • Recent lower extremity surgery or injury
  • Musculoskeletal or neurological conditions interfering with exercise participation
  • Contraindications to blood flow restriction training
  • Participation in another structured exercise trial during the study period

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: BFR Exercise Group
Participants will perform a supervised low-load exercise program twice weekly for 8 weeks combined with blood flow restriction applied to both proximal thighs at 50-60% of individually determined arterial occlusion pressure during the strengthening component of the intervention.
Device: Blood Flow Restriction Training
Low-load exercise performed with individualized blood flow restriction applied to both proximal thighs using pneumatic cuffs inflated to 50-60% of arterial occlusion pressure.
Behavioral: Low-Load Exercise Program
Participants will perform a supervised low-load exercise program twice weekly for 8 weeks. The exercise program will include warm-up activities, quadriceps-focused strengthening exercises, cycling exercise, and cool-down activities. The same exercise program will be applied to all study groups.
Sham Comparator: Sham BFR Group
Participants will perform the same supervised low-load exercise program twice weekly for 8 weeks. Pneumatic cuffs will be applied to both proximal thighs but inflated to a pressure insufficient to produce meaningful vascular occlusion.
Behavioral: Low-Load Exercise Program
Participants will perform a supervised low-load exercise program twice weekly for 8 weeks. The exercise program will include warm-up activities, quadriceps-focused strengthening exercises, cycling exercise, and cool-down activities. The same exercise program will be applied to all study groups.
Device: Sham Blood Flow Restriction
Low-load exercise performed with pneumatic cuffs applied to both proximal thighs but inflated to a pressure insufficient to produce meaningful vascular occlusion.
Active Comparator: Exercise Control Group
Participants will perform the same supervised low-load exercise program twice weekly for 8 weeks without blood flow restriction.
Behavioral: Low-Load Exercise Program
Participants will perform a supervised low-load exercise program twice weekly for 8 weeks. The exercise program will include warm-up activities, quadriceps-focused strengthening exercises, cycling exercise, and cool-down activities. The same exercise program will be applied to all study groups.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Rectus Femoris Muscle Thickness
Time Frame: Baseline and Week 8
Rectus femoris muscle thickness will be assessed using B-mode ultrasonography. Measurements will be obtained at baseline and after the 8-week intervention period. The primary outcome will be the change in rectus femoris muscle thickness from baseline to post-intervention.
Baseline and Week 8

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Hanifi Bal

Collaborators

Dicle University

Investigators

  • Study Director: seçil özkurt, Dr., Istinye University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

July 1, 2026

Primary Completion (Estimated)

March 1, 2027

Study Completion (Estimated)

April 1, 2027

Study Registration Dates

First Submitted

June 9, 2026

First Submitted That Met QC Criteria

June 9, 2026

First Posted (Actual)

June 12, 2026

Study Record Updates

Last Update Posted (Actual)

June 12, 2026

Last Update Submitted That Met QC Criteria

June 9, 2026

Last Verified

June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • RRMS-BFR-RCT-2026

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant data will not be made publicly available because the informed consent obtained from participants does not include permission for public data sharing and institutional policies restrict release of participant-level data.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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