Dynamic postural control in individuals with and without chronic ankle instability-do the modified star-excursion balance test and jump-landing stabilization have the same control mechanism?

Objective: To examine the relationship between two dynamic postural tasks in subjects with and without chronic ankle instability (CAI). Design: Cross-sectional study. Setting: Biomechanics lab. Participants: Thirty subjects with CAI and 30 healthy controls. Main outcome measure: Performance of two dynamic postural control tests: the modified Star-Excursion Balance Test (mSEBT) and an assessment of a single limb jump-landing on a force plate that yielded two outcomes: time to stabilization (TTS) and the absolute average force in the mediolateral plane during the first 0.4 s after landing (AAF_ML). Results: In the CAI group, a significant correlation was found between the mSEBT score and the AAF_ML (ρ = −0.54, p < 0.01), but not between the mSEBT or TTS or between the AAF_ML and the TTS. However, in the control group, a significant correlation was found between AAF_ML and the TTS (ρ = 0.43, p < 0.05), but not between the mSEBT and TTS or between the mSEBT and AAF_ML. Conclusion: These results suggest that there is no association between the different dynamic balance tasks. The different pattern of association in individuals with CAI may indicate altered central neural control. Clinicians and researchers should therefore not use a single task to assess dynamic postural control.