Comparing the effect of cognitive demand on dynamic postural control in functional ankle instability, ankle sprain copers and healthy individuals.

Some individuals, copers, despite of an acute lateral ankle sprain could return to high-level physical activities, without development of functional ankle instability (FAI). Study about differences between copers and FAI groups results in identify factors that cause FAI. The aim of this study was to compare the effect of cognitive demands on dynami postural control in FAI, copers and uninjured controls. 42 individuals in three groups with FAI, copers and uninjured controls participated in this study. Dynamic postural stability with and without cognitive demands, was assessed. Repeated measure ANOVAs was used to determine possible significant interactions for the 2 factors. Interaction of group by cognitive difficulty was significant for Overal stability index (OSI) (P<0.001) and mediolateral stability index (MLSI) (P=0.005). A significant increase in OSI and MLSI observed in FAI group during dual task compared to the single task performance (p<0.05). However, a significant decrease in OSI was demonstrated in copers during dual task condition (p=0.004). The results showed that concurrent performance of cognitive task could effect on postural control after first lateral ankle sprain. responses to cognitive perturbations can consider as an important factor to identify adaptation mechanisms in copers and distinguish between copers and FAI groups.