The Dynamic Postural Control Is Impaired in Patients with Chronic Ankle Instability: Reliability and Validity of the Multiple Hop Test

Objective: To investigate the reliability and validity of a clinical evaluation method for the assessment of the dynamic Postural control in patients with chronic ankle instability (CAI). Design: Cross-sectional study. Setting: All tests were conducted at the practice room of the Physical Therapy Department. Participants: Twenty-nine healthy subjects and 29 patients with CAI were selected. Interventions: Participants performed twice a multiple hop test within a 1-week time interval. Subjects hopped on 10 different tape markers while trying to avoid any postural correction. Main Outcome Measures: The number and type of balance errors were documented by analyzing the digital video images. Results: Test-retest reliability of the number of balance errors was excellent in patients (intraclass correlation coefficient, ICC = 0.83; standard errors of measurement = 2.6) and moderate in healthy subjects (ICC = 0.64; standard errors of measurement = 2.8). The intra-observer and inter-observer reliability was excellent (ICC > 0.90). Both for the test (P = 0.000) and for the retest (P = 0.000), the number of balance errors in patients was significantly higher (17.9 +/- 6.6) when compared with healthy subjects (10.9 +/- 4.6). On both test occasions, patients with CAI used significantly more a change-in-support strategy (test: P = 0.000; retest: P = 0.000). The number of balance errors was significantly correlated with the time needed to perform the test (r = 0.60; P = 0.000) and the perceived difficulty of the hop test as rated on a visual analogue scale (r = 0.44; P = 0.014). Conclusions: The multiple hop test is a reliable and valid test for detecting an impaired dynamic postural control in patients with CAI.