Optimal Number of Practice Trials for Balance and Hop Tests in Individuals with Chronic Ankle Instability

Background: Static and dynamic balance tests and hop tests are widely used to assess lower extremity function; however, scientific evidence regarding the optimal number of practice trials remains limited. Purpose: To determine the number of practice trials necessary to achieve consistent performance on static and dynamic balance tests and hop tests in males and females. Study Design: Cross-sectional study. Methods: One hundred individuals (50 males, 50 females) with chronic ankle instability were recruited to participate in this study. Each participant performed the Star Excursion Balance Test (SEBT), the single-leg stance test using the Biodex Balance System (BBS), the triple-crossover hop (TCH) test, and the figure-of-8 hop (F8H) test across two sessions separated by two to three days. Main outcome measures included normalized reach distances in the anterior (ANT), posteromedial (PM), and posterolateral (PL) directions of the SEBT; overall stability index (OSI), anterior-posterior stability index (APSI), and medial-lateral stability index (MLSI) from the BBS; distance (m) in the TCH test; and time (s) from the F8H test. Two-way repeated measures analysis of variance was used to examine group-by-trial interactions and main effects, with pairwise comparisons and Bonferroni adjustments for post hoc analysis. Intraclass correlation coefficients, standard error of measurement, and minimal detectable change were calculated to assess reliability and performance stabilization. Results: A significant group-by-trial interaction was observed for the hop tests, but not for the SEBT and BBS. In the TCH test, males required more than six practice trials, whereas females required at least five trials. In the F8H test, males and females required at least five and three trials, respectively. For the SEBT and BBS, participants required at least four, three, and four practice trials for the ANT, PM, and PL directions, and four, two, and five trials for the OSI, APSI, and MLSI, respectively, regardless of sex. Conclusion: The number of practice trials required for the TCH and F8H tests differs between males and females. In contrast, the number of practice trials required for the SEBT and BBS is not influenced by sex. Males appear to need more practice trials than females to achieve consistent performance. Therefore, researchers and clinicians should implement sex-specific practice trial protocols for hop tests to ensure accurate data collection. Level of Evidence: Level 3b.