Article ID: 26-E00024
Objectives: The present study investigated the acute effects of bilateral plantar electrical muscle stimulation (EMS) on dynamic standing performance and lower limb muscle activity in healthy adults using a commercially available device. Methods: Fifteen healthy young adults completed a randomized crossover study involving control (CON) and bilateral plantar EMS conditions separated by at least 24 hours. EMS was applied for 12 minutes while participants were seated, with the total intervention time standardized to 15 minutes across conditions. Dynamic standing performance was assessed using the Functional Reach Test (FRT) and center-of-pressure (COP) parameters, and muscle activity was measured using surface electromyography. Normally distributed outcomes were analyzed using 2-way repeated-measures analysis of variance (ANOVA) and non-normally distributed outcomes using the Friedman test. Exploratory associations between percentage changes in muscle activity and dynamic standing performance were assessed using Spearman’s rank correlation coefficients. Results: The primary analyses revealed no significant main effects of condition or time, condition × time interactions, or overall differences according to the Friedman test. Exploratory analysis revealed a positive correlation between percentage changes in tibialis anterior activity and FRT distance in the EMS condition (ρ = 0.57, p = 0.03). No other significant correlations or adverse events were observed. Conclusions: Bilateral plantar EMS did not significantly change lower limb muscle activity or dynamic standing performance in healthy adults. The exploratory association between tibialis anterior activity and FRT distance is hypothesis-generating and does not establish a causal effect of EMS on sensorimotor control. Further studies in larger samples and in populations with impaired sensorimotor function are warranted.
