Schwiertz Gerrit, Brueckner Dennis, Schedler Simon, Kiss Rainer, Muehlbauer Thomas
Division of Movement and Training Sciences/Biomechanics of Sport, University of Duisburg-Essen, Essen, Germany.
Department of Health and Social Affairs, FHM Bielefeld - University of Applied Sciences, Bielefeld, Germany.
Gait Posture. 2019 Jan;67:142-146. doi: 10.1016/j.gaitpost.2018.10.011. Epub 2018 Oct 10.
The Lower Quarter Y Balance Test (YBT-LQ) has been widely used in the field to assess dynamic balance performance in various populations. However, no study has demonstrated test-retest reliability of the YBT-LQ in adolescents including several age cohorts, even though reliability is necessary to provide repeatable performance data.
Thus, we examined test-retest reliability of the YBT-LQ in healthy adolescents.
In a school setting, 178 secondary school students (93 female, 85 male) in sixth to eleventh grades (11-19 years) performed the YBT-LQ twice, 7 days apart. Normalized maximal reach distances (% leg length) for all three directions (i.e., anterior, posterolateral, posteromedial) and both legs and the composite score were used as outcome measures. Intraclass correlation coefficient (ICC) and standard error of measurement (SEM) were calculated to assess relative and absolute test-retest reliability, respectively. Practical relevance of the YBT-LQ was determined by calculating the minimal detectable change (MDC).
Irrespective of grade, test-retest reliability for all distances reached was predominately "excellent" (i.e., ICC > 0.75) and the rather small SEM values ranged from 1.77 to 5.81%. Depending on grade and reach direction, MDC values of 4.90 to 16.10% represent the minimum amount of change needed to identify clinically relevant effects in repeated measurements of the YBT-LQ performance.
The observed values suggest that the YBT-LQ is a reliable test and suitable to detect changes of dynamic balance performance in healthy adolescents from grade six to eleven (i.e., aged 11-19 years).
下半身Y平衡测试（YBT-LQ）已在该领域广泛用于评估不同人群的动态平衡能力。然而，尚无研究证明YBT-LQ在包括多个年龄组的青少年中的重测信度，尽管信度对于提供可重复的性能数据是必要的。
因此，我们检验了YBT-LQ在健康青少年中的重测信度。
在学校环境中，178名六至十一年级（11 - 19岁）的中学生（93名女生，85名男生）进行了两次YBT-LQ测试，间隔7天。将三个方向（即前向、后外侧、后内侧）以及双腿的标准化最大伸展距离（%腿长）和综合得分用作结果指标。计算组内相关系数（ICC）和测量标准误差（SEM），分别评估相对和绝对重测信度。通过计算最小可检测变化（MDC）来确定YBT-LQ的实际相关性。
无论年级如何，所有达到的距离的重测信度大多为“优秀”（即ICC > 0.75），且SEM值相当小，范围为1.77%至5.81%。根据年级和伸展方向，MDC值在4.90%至16.10%之间，代表在重复测量YBT-LQ表现时识别临床相关效应所需的最小变化量。
观察到的值表明，YBT-LQ是一种可靠的测试，适用于检测六至十一年级（即11 - 19岁）健康青少年的动态平衡能力变化。
