Interplay Between Postural Stability and Coordination in Female Soccer Players With Chronic Ankle Instability

This study investigated the effects of chronic ankle instability (CAI) on postural control following landing with an unanticipated task and on shank-rearfoot coordination during side-cutting in female soccer players. The association between postural stability and coordination patterns was investigated to identify shared control characteristics across tasks.

Eighteen female soccer players were categorized into CAI (n = 10) and control (n = 8) groups. Participants performed 20-s single-leg stances and side-cutting following landing with an unanticipated task. Postural control during single-leg stance was quantified using the largest Lyapunov exponent of the mediolateral center of pressure. Shank-rearfoot coordination during side-cutting was analyzed using a modified vector-coding technique.

The CAI group exhibited a significantly lower largest Lyapunov exponent of mediolateral center of pressure during single-leg stance (p = .043). During side-cutting, the CAI group demonstrated an increased proportion of in-phase with distal dominancy during the deceleration phase (p = .027). Within the CAI group, largest Lyapunov exponent was associated with coordination patterns, where a negative correlation with anti-phase with proximal dominancy and a positive correlation with in-phase with distal dominancy (r = -.680 and .648, respectively; p < .050) were observed.

Female soccer players with CAI exhibit reduced adaptability to postural control following landing with an unanticipated task and diminished flexibility in shank-rearfoot coordination during sport-specific cutting. The observed association between static postural instability and altered dynamic coordination may reflect a reduced capacity to flexibly modulate control strategies in patients with CAI, which may be related to the risk of recurrent ankle sprains.