Replication study: Investigating the effects of maximal anaerobic fatigue on dynamic postural control using the Y-Balance Test

Objectives: The aim of this study was to replicate the study titled “Investigating the effects of maximal anaerobic fatigue on dynamic postural control using the Y-Balance Test” by Johnston et al. (2018) as part of a large replication project. This study aimed to determine the effects of maximal anaerobic fatigue on dynamic postural control using the Y-Balance Test, with a specific focus on anterior reach distance. Design: A single session intervention. Methods: Forty male and female university students (age: 22 ± 3 years, height: 171.88 ± 8.96 cm, mass: 76.20 ± 14.31 kg) partaking in competitive sport, completed a Y-Balance Test protocol at 20, 10, and 0 min before a modified 60 s Wingate fatiguing protocol. Post-fatigue assessments were completed at 0, 10, and 20 min after the Wingate test. Replication outcomes included significance, direction, and effect size comparison using a z-test. Results: A one-way repeated measures ANOVA showed a significant effect for maximal anaerobic fatigue on normalised anterior reach direction (F_{1.82, 69.03} = 7.16, p = 0.002, η_p² = 0.159; 95 % CI: 0.025, 0.320). Therefore, we replicated the original findings for anterior reach distance in terms of statistical significance (F = 3.818, p = 0.025, η_p² = 0.376; 95 % CI: 0.00, 0.62). The replication and original effect size estimates for anterior reach direction were compared using a z-test and were deemed compatible (z = 1.65, p = 0.05). Conclusions: Overall, we replicated the original study findings for the effect of maximal anaerobic fatigue on anterior reach distance in a Y-Balance Test.