Effects of blood flow restriction therapy on lower-limb strength in multiple sclerosis: A systematic review and meta-analysis.

BACKGROUND: Multiple sclerosis (MS) is a chronic neurodegenerative disease that impairs muscle strength, gait, and functional capacity. Blood flow restriction (BFR) therapy has emerged as a promising low-load rehabilitation strategy, although evidence in people with MS (pwMS) remains limited and heterogeneous. OBJECTIVE: To analyze the current scientific evidence regarding the effects of BFR therapy on lower-limb muscle strength in pwMS. METHODS: PRISMA-based review included a systematic search of eight electronic databases. Clinical and quasi-experimental studies involving people with MS that evaluated lower-limb BFR interventions were included, with lower-limb muscle strength as the primary outcome. The primary outcome for meta-analysis was de standardized mean differences (SMD) in strength. Methodological quality and risk of bias were assessed using the PEDro, JBI scales, RoB 2 and ROBINS-I V2 tools. RESULTS: Five studies met the inclusion criteria. Interventions ranged from 6 to 12 weeks with low training loads (30-40% of one-repetition maximum) and occlusion pressures ranging from 30% to 80% of arterial occlusion pressure. Compared with exercise alone, exercise combined with BFR significantly improved quadriceps (SMD=-0.55) and hamstring strength (SMD=-0.38), and possibly reduced fatigue (SMD=-0.35), with low heterogeneity across analyses. However, the statistical significance of the effect on quadriceps strength was lost in the sensitivity analysis. Methodological quality and overall risk of bias varied from moderate to good. CONCLUSIONS: BFR therapy may improve lower-limb strength (more consistently for hamstrings than quadriceps) and may reduce fatigue in people with MS compared with exercise alone, but the certainty of the evidence is low. The quadriceps effect was not robust to sensitivity analysis, and no clear benefit was found for sit-to-stand or gait outcomes. The evidence does not allow conclusions on equivalence to high-load training or on optimal occlusion pressure or intervention duration. Lager, high-quality randomized trials are needed.