Testing dynamic balance in youth female volleyball players: development, reliability and usefulness

Abstract

Purpose.The aim of this research was to develop a dynamic balance test and examine its reliability by comparing first trial results with the average and best ones from multiple attempts.Methods.Overall, 32 volleyball players (aged 11.3 ± 0.67 years) were investigated in 2 sessions (with a 14-day interval), each consisting of 3 trials of the modified bench walk with 3 turns (MBW3T) test. Three test methods were compared: first trial (MBW3T<sub>trial1</sub>), average result (MBW3T<sub>mean</sub>), and best result (MBW3T<sub>best</sub>). A paired-sample <i>t</i>-test determined differences with an effect size. Test-retest reliability was assessed with an intraclass correlation coefficient.Results.The paired-sample <i>t</i>-test revealed no significant difference in performance between test and retest for MBW3T<sub>trial1</sub> (<i>t</i> = 0.01, <i>p</i> = 0.99), MBW3T<sub>mean</sub> (<i>t</i> = –0.46, <i>p</i> = 0.65), and MBW3T<sub>best</sub> (<i>t</i> = –1.05, <i>p</i> = 0.30). Standard error of measurement (SEM) as the absolute reliability within-individual variation parameter showed that MBW3T<sub>trial1</sub> had higher variation than MBW3T<sub>mean</sub> and MBW3T<sub>best</sub>, in which the measurement error was minimal. To identify usefulness, we calculated the smallest worthwhile change and compared it with SEM for different effect sizes; the test was rated marginal to satisfactory. The study results indicated fair reliability when the first trial was observed and good reliability for the mean and best of 3 trials.Conclusions.MBW3T<sub>mean</sub> and MBW3T<sub>best</sub> are cheap, simple, reliable, and marginal to satisfactory useful measures for assessing dynamic balance in youth female volleyball players and can be used in scientific and practical settings.