Reliability and Responsiveness of the Star Excursion Balance Test in those with Chronic Ankle Instability

Abstract

The Star Excursion Balance Test (SEBT) is a dynamic postural control assessment which examines lower extremity maximal reach distances while maintaining contralateral single limb stance. This test has detected postural control deficits and improvements following rehabilitation in those with chronic ankle instability (CAI). Despite these findings, the reliability and standards for determining meaningful change have not been reported for this group. PURPOSE: To determine test-retest reliability and minimal detectable change (MDC) scores for the SEBT in those with CAI. METHODS: The SEBT was assessed on 2 separate days (∼6 days apart) in 8 individuals with self-reported CAI (2 males, 6 females, age 23 ± 5 yrs). Subjects were included if they reported at least 1 ankle sprain, 2 episodes of ankle "giving way" in the past 3 months, and disability scores of ≤90% on the Foot and Ankle Ability Measure (FAAM) and ≤80% on the FAAM-Sport. The anterior (ANT), posteromedial (PM), and posterolateral (PL) reach directions of the SEBT were selected based on previous studies. All trials were performed barefoot with the stance leg centered in the star. In each test session, subjects performed 4 consecutive practice trials in each direction. Following the practice trials, 3 trials were performed in each direction and used for analysis. In the event of an error, the trial was discarded and repeated. Reach distances were measured in cm and normalized to leg length. Reliability was determined using intraclass correlation coefficients (ICC 2,1) and standard error of measurement (SEM). MDC was calculated with a 95% level of confidence. RESULTS: The ANT direction had the highest reliability (ICC = 0.92, SEM = 1.66) and the lowest MDC score (4.72%) followed by the PM direction (ICC = 0.86, SEM = 2.56; MDC = 7.32%). The PL direction was associated with the lowest reliability (ICC = 0.74, SEM = 3.83) and highest MDC score (10.79%). CONCLUSION: The results of this study indicate the SEBT has suitable reliability for assessing dynamic postural control in those with CAI. MDC scores suggest alterations in reach distance ranging from 4.72 -10.79% are required to identify changes which exceed the variability associated with the measure. MDC values are important for outcome assessment and goal setting when using the SEBT to monitor rehabilitation progression.