Dorsiflexion and dynamic postural control deficits are present in those with chronic ankle instability

To determine if differences in weight-bearing ankle dorsiflexion range of motion (DFROM) and Star Excursion Balance Test (SEBT) reach distances were present between participants with chronic ankle instability (CAI) and healthy individuals. A secondary objective was to re-examine the relationship between these measures in participants with and without CAI.Case-control.Thirty participants with CAI were matched to 30 healthy participants. All participants performed maximum reach in the anterior, posteromedial and posterolateral directions of the SEBT; as well as, the Weight-Bearing Lunge Test (WBLT) to measure DFROM. Dependent variables included maximal DFROM (cm) and normalized SEBT reach distances (%). Independent t-tests were used for group comparisons (a priori p ≤ 0.05). Simple-linear regression examined the relationship between the WBLT and each SEBT direction.Significant differences were detected between groups for the WBLT (CAI: 10.73 ± 3.44 cm, healthy: 12.47 ± 2.51 cm; p=0.03) and anterior reach distance (CAI: 76.05 ± 6.25%, healthy: 80.12 ± 5.88%; p=0.01). No differences were identified in posteromedial or posterolateral (ps>0.70) reach. The WBLT had a significant moderate correlation to anterior reach in both groups (ps<0.05) but was not significantly correlated to posteromedial or posterolateral reach distance (ps>0.70).The results indicate that participants with CAI demonstrated less DFROM and anterior SEBT reach distance compared to health controls. Additionally, both groups demonstrated similar correlations between WBLT and SEBT performance. These findings suggest that participants with CAI have alterations in ankle motion which may negatively influence dynamic postural control; however, the relationship between WBLT and SEBT performance is consistent in those with and without CAI.