Performance Differences Between the Modified Star Excursion Balance Test and the Y-Balance Test in Individuals With Chronic Ankle Instability

Context: The modified Star Excursion Balance Test (mSEBT) and Y-Balance Test (YBT) are common dynamic postural stability assessments for individuals with chronic ankle instability (CAI). However, the reach distance measurement technique and movement strategy used during the mSEBT and YBT differ. To date, no studies have compared task performance differences on these tests in CAI patients. Objective: To determine whether individuals with CAI perform the mSEBT and YBT differently. Design: Cross-sectional. Setting: Biomechanics laboratory. Participants: Of 97 consented participants, 86 (43 females, 43 males; age 21.5 [3.3] y, height 169.8 [10.3] cm, mass 69.5 [13.4] kg), who reported 525 on the Cumberland Ankle Instability Tool, 11 on the Identification of Functional Ankle Instability, and had a history of a moderate to severe ankle sprain(s) participated. Interventions: Participants were instructed to perform the mSEBT and YBT in a predetermined counterbalanced order. Three anterior, posteromedial, and posterolateral trials of each test were completed on the involved limb after 4 practice trials. Test direction order was randomized for each participant. Main Outcome Measures: Normalized (expressed in percentage) reach distance in each direction. Paired sample I tests were performed to compare each of the 3 directions between the mSEBT and YBT. Results: Significantly shorter reach distances in the anterior (58.9% [5.8%] vs 61.4% [5.4%], P = .001) and the posteromedial (98.8% [8.6%] vs 100.8% [8.1%], P = .003) directions were noted on the mSEBT relative to the YBT. No differences in the posterolateral directions were observed. Conclusions: Within those with CAI, mSEBT and YBT normalized reach distances differ in the anterior and posteriomedial directions. As a result, clinicians and researchers should not directly compare the results of these tests.