Reduced ankle muscle activity under cognitive loads in individuals with chronic ankle instability: A cross-sectional study.

OBJECTIVES

To investigate the influence of cognitive demands on postural stability and ankle muscle activity during static and dynamic postural control in individuals with chronic ankle instability (CAI).

PARTICIPANTS

21 individuals with CAI (age = 21.7 ± 1.5 years) MAIN OUTCOME MEASURES: Postural stability was assessed using time-to-boundary (TTB) measures and normalized reach distances from the modified Star Excursion Balance Test (mSEBT). Ankle muscle activity was evaluated using integrated electromyography (iEMG) from tibialis anterior (TA), peroneus longus (PL), medial gastrocnemius (MG), and soleus muscles (SL).

RESULTS

No significant differences in postural stability were observed between single- and dual-task conditions. However, ankle muscle activity significantly decreased under dual-task conditions. Specifically, MG (P = 0.002) and SL (P = 0.009) activity decreased during eyes-open static postural control. During dynamic postural control, TA activity decreased in posteromedial (P = 0.010) and posterolateral (P = 0.007) reaches, while PL decreased in posterolateral reach (P = 0.038). Concurrent cognitive performance did not differ significantly across postural tasks.

CONCLUSION

Cognitive loading reduced ankle muscle activity without impairing postural stability, suggesting that cognitive loading influences neuromuscular responses during postural control in individuals with CAI. These findings highlight the importance of considering cognitive demands during postural control assessment.