Modified star excursion balance test performance in individuals with chronic ankle instability: a participant-level analysis

Introduction: For 1 in 5 individuals, an initial ankle sprain results in chronic ankle instability (CAI). Research is inconclusive as to whether individuals with CAI display decreased stability performance. This study conducted a participant-level analysis to determine normative values for modified Star Excursion Balance Test (mSEBT) performance in a CAI population. Design: Participant-level analysis. Methods: Ten datasets of mSEBT data were combined and participants categorised into one of three groups: individuals with CAI, Copers and Healthy participants. Maximal reach distances were analysed in the anterior (ANT), posterolateral (PL), posteromedial (PM) and composite (COMP) directions. The CAI and Healthy groups were sub-categorised into 4 groups depending on the stance position and whether the average or best scores were reported. Results: The final pooled data consisted of 429 participants (202 CAI; 181 Healthy; 46 Coper). The 4 CAI sub-groups recorded a mean reach of 66.53%–76.42% (ANT), 54.67%–87.16% (PM), 44.55%–83.01% (PL) and 55.25%–82.19% (COMP). Smaller reach distances were reported in Group 1's ANT, PL and COMP reaches and Group 2's ANT reach (p < 0.05) compared to the Healthy group. Copers exceeded CAI and Healthy reaches for all reaches. Reach distances in the ANT direction were generally the smallest for the CAI group and ANT and PL directions for the Healthy and Coper groups. Conclusion: Reduced mSEBT reach was performed in specific directions for specific sub-groups only for the CAI population compared to both Healthy and Coper. The normative data can inform clinical practice and aid decision-making regarding dynamic balance for assessment and rehabilitation purposes.