Assessing the Y-Balance Test: Relationship With Strength and Functional Performance Following ACL Reconstruction

OBJECTIVE: To investigate the relationship between dynamic postural control measured by the Lower Quarter Y-Balance Test (YBT-LQ) and functional outcomes in individuals following anterior cruciate ligament injury. DESIGN: Longitudinal cohort study METHODS: Limb Symmetry Index (LSI) scores for the YBT-LQ were assessed for 55 patients with anterior cruciate ligament reconstruction, at 3 and 9 months postoperatively. Functional performance was evaluated using isokinetic strength measurements and functional tests. We analyzed changes in YBT-LQ scores with paired t tests and examined the relationship between YBT-LQ scores and functional outcomes with Pearson’s r. Multiple regression analysis assessed the predictive value of 3-month YBT-LQ scores for 9-month functional measures. RESULTS: YBT-LQ LSI scores improved significantly from 3 to 9 months postoperative ( P<.01). Individual reach direction scores did not change. There were weak to moderate correlations between anterior YBT-LQ scores and drop jump LSI ( r = 0.43, P = .01), and between posterolateral YBT-LQ scores and isokinetic flexion ( r = 0.33, P = .04). Three-month YBT-LQ scores did not predict 9-month functional outcomes. CONCLUSION: The YBT-LQ, despite its clinical utility in assessing dynamic postural control, may be insufficient when used in isolation for return-to-sport decisions. JOSPT Open 2026;4(1):121-127. Epub 10 November 2025. doi:10.2519/josptopen.2025.0170