Leg muscle microvascular function is associated with dynamic but not static balance performance in older adults

Balance impairments in older adults significantly increase fall risk and are a growing public health concern. While muscle strength and mass have been extensively studied in relation to balance, the role of skeletal muscle microvascular function remains unclear. The purpose of this study was to evaluate whether skeletal muscle microvascular function is associated with static and dynamic balance in healthy older adults. This cross-sectional study included 57 healthy community-dwelling older adults aged 60–75. Static balance was assessed under four conditions (eyes open/closed, on firm/foam surface) using center of pressure metrics. Dynamic balance was evaluated using the Y Balance Test (YBT). Microvascular function of the tibialis anterior (TA) and medial gastrocnemius (MG) was assessed via near-infrared spectroscopy and post-occlusive reactive hyperemia, using TSI10 (initial reperfusion slope), TSI1/2 (recovery half-time), TSIdesaturation (total desaturation magnitude), and TSIrecovery (total recovery magnitude) as key indicators. Multiple linear regression analyses were performed to assess associations between microvascular and balance parameters, adjusting for age, sex, grip strength, body fat percentage, and estimated VO₂max. No significant associations were found between microvascular parameters and static balance outcomes across any testing conditions. For dynamic balance, after adjusting for age, sex, grip strength, body fat percentage, and estimated VO₂max, MG TSIrecovery was significantly and positively associated with YBT performance on both dominant and non-dominant legs (both p < 0.05). In addition, MG TSI10 was significantly associated with YBT performance on the dominant leg (p < 0.05). No significant associations were found between TA microvascular parameters and dynamic balance performance (all p > 0.05). This study demonstrates that microvascular function in the leg is associated with dynamic but not static balance performance in older adults.