Acute effects of upper-limb blood flow restriction training on dual-task postural control and physiological correlates in older adults

Background: Falls represent a major health concern in older adults, underscoring the need for interventions that enhance postural control. This study investigated whether applying blood flow restriction (BFR) during short-term arm ergometry training improves posture–cognition dual-task performance and adaptive changes in cortical–postural coupling. Methods: Twenty-six older adults (12 males, 14 females; 69.1 ± 3.0 years) completed a single 21-minute session of arm ergometry with gender-specific workloads, either combined with BFR at 80% systolic pressure or without restriction (control). Dual-task performance, balance dynamics, and cortico-postural phase–amplitude coupling (PAC) were assessed during concurrent light-pod tapping and stance on an unstable foam surface. Results: Compared with controls, the BFR condition resulted in greater reductions in center of pressure (COP) area (p = 0.002) and velocity (p = 0.003), indicating improved postural control. Stabilogram diffusion analysis further revealed reductions in critical displacement (CD, p < 0.001) and short-term diffusion coefficient (Ds, p = 0.002), suggesting decreased sway variability and enhanced postural regulation. Phase–amplitude coupling (PAC) analysis showed a significant between-condition difference in the theta band at the frontal region of interest, with greater negative modulation under BFR compared with NBFR (p = 0.016). In contrast, no significant between-condition differences were observed in the alpha or beta PAC (p > 0.05). These findings indicated frequency-specific modulation of cortico–postural coupling associated with upper-limb BFR training. Conclusion: Arm ergometry combined with BFR is associated with improved dual-task postural performance in older adults. These changes were accompanied by frequency-specific modulation of cortico–postural coupling, evident in the theta band at frontal regions. These findings suggest that upper-limb BFR training may represent a feasible and accessible intervention for improving balance under dual-task conditions in aging populations.