Objective: Postural control during single-leg stance requires coordinated neuromuscular strategies that adapt to changes in sensory input.Although visual information is essential for balance regulation, direction-specific muscle activation strategies associated with altered visual conditions during single-leg stance remain unclear.This study aimed to investigate the correlation between lower extremity muscle activation and direction-specific center of pressure (COP) displacement under different visual conditions.Design: Cross-sectional study.Methods: Forty healthy young adults (20 males and 20 females) participated in this study.Surface electromyography (sEMG) was used to assess the activation of the gluteus medius, rectus femoris, tibialis anterior, and gastrocnemius muscles during single-leg stance.COP displacement in the mediolateral (ML) and anteroposterior (AP) directions was measured using force plates under eyes-open and eyes-closed conditions.Spearman correlation analysis was conducted to examine the relationships between muscle activation and COP displacement.Results: Under the eyes-open condition, ML COP displacement showed a negative correlation with gluteus medius activation and a positive correlation with tibialis anterior activation (p0.05).Under the eyes-closed condition, ML COP displacement was positively correlated with gluteus medius, rectus femoris, and gastrocnemius activation (p0.05).AP COP displacement under eyes-closed conditions was positively correlated with rectus femoris and gastrocnemius activation (p0.05).Conclusions: These findings provide preliminary evidence that direction-specific muscle activation strategies during single-leg stance vary according to visual conditions.The results may serve as fundamental data for understanding neuromuscular control strategies during single-leg stance.
Song et al. (Mon,) studied this question.