Static and dynamic postural control of the ankle during the performance of the Y Balance Test and Leg Stance Test in subjects with and without chronic ankle instability

Introduction: Lateral ankle sprain (LAS) is one of the most common musculoskeletal injuries and it is estimated that up to 40% of acute ankle sprains can end up developing Chronic Ankle Instability (CAI). Literature shows that individuals with CAI have a higher probability of having both static and dynamic postural control deficits. Although, there is a lack of consistency in the studies detecting postural control deficits in subjects with CAI. Objectives: Compare individuals with and without CAI in static and dynamic postural control using the Y Balance Test (YBT) and posturography measures in the Leg Stance Test (LST). Additionally, check if there is a correlation between the reach distance on the YBT and the LST results. Design: Cross-sectional comparative observational study and correlation study. Methods: This study had a total of 42 participants, 19 in the CAI group and 23 in the healthy group. Selection criteria were based on the International Ankle Consortium position statement for CAI sample studies. To allocate the participants to each group we used the Identification of Functional Ankle Instability (IdFAI) where a cut-off of 11 points was used. All participants performed the YBT and the LST. The reached distance on the YBT and the posturographic variables while performing the LST were compared between subjects with and without CAI. Additionally, we searched for a correlation between the YBT reach distance and the results of the CoP displacement measures on the LST. Results: No significant differences (p>0,05) were found between groups in any reach distance of the YBT and there were also no significant differences (p>0,05) in LST posturographic measures. When examining the correlation between reach distance in the YBT with the CoP measures from the LST, there was not found a strong correlation (Spearman’s Rho < ±0,40) between the variables studied. Conclusions: The results indicate that there is no significant difference between individuals with and without CAI in dynamic and static postural control using YBT and LST, respectively. Additionally, there is no strong correlation between the results of the YBT and LST in both groups. This results interpretation should be done carefully due to our modest sample. Our study showed that YBT and LST are not the best tests to use when assessing individuals with CAI or, at least, they should not be used exclusively