Effects of short foot exercises with and without blood flow restriction on Foot Posture Index, sensory organization, and center of pressure displacement in middle-aged women with flexible flatfoot: a randomized controlled trial

Flexible flatfoot is a common musculoskeletal disorder in middle-aged women, causing collapse of the medial longitudinal arch, biomechanical alterations, impaired sensory organization, and increased postural instability. This randomized controlled trial compared the effects of 6 weeks of short foot exercises (SFE) with and without blood flow restriction (BFR) on Foot Posture Index (FPI-6), sensory organization, and center of pressure (COP) displacement. In this assessor-blinded RCT, 60 middle-aged women (35–55 years) with flexible flatfoot (FPI-6 > 6) were randomly allocated to SFE + BFR ( n = 30) or SFE alone ( n = 30). Both groups performed identical SFE protocols (3 sessions/week, 45 min/session for 6 weeks). The BFR group used proximal-shank cuff pressure at 40–80% limb occlusion pressure. Outcomes included FPI-6, equilibrium scores, and COP displacement in mediolateral (X) and anteroposterior (Y) axes across six Sensory Organization Test (SOT) conditions, measured via NeuroCom dynamic posturography at baseline and post-intervention. Data were analyzed using mixed 2 × 2 × 6 ANOVA (SPSS v27, α = 0.05). All participants completed the study with no adverse events. Both groups showed significant within-group improvements in FPI-6, equilibrium scores (most SOT conditions), and COP stability (particularly Y-axis; all P < 0.05). No significant between-group differences were found for any outcome (all P > 0.05), with large within-group effect sizes (ηp 2 = 0.45–0.78). Six weeks of SFE, with or without BFR, significantly improved foot posture, sensory organization, and postural stability in middle-aged women with flexible flatfoot. Under the current protocol and within the limitations of this study, BFR did not confer additional statistically significant benefit. SFE is a safe and effective intervention for this population; its cost‑effectiveness warrants further economic evaluation. The trial was prospectively registered at the UMIN Clinical Trials Registry (UMIN000061327; link: https://center6.umin.ac.jp/cgi-bin/ctr_e/ctr_view.cgi?recptno=R000070174 ) .