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

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.