Lower Quarter Y Balance Test performance: Reference values for healthy youth aged 10 to 17 years.

Background: The Lower Quarter Y Balance Test (YBT-LQ) has been widely used to register dynamic balance performance in children and adolescents. However, studies evaluating age- and sex-specific normative data to assess and classify YBT-LQ performance for these age-cohorts are missing.
Objective: Thus, we investigated YBT-LQ performance in healthy youth to provide age- and sex-specific reference values.
Methods: Six-hundred and sixty-nine individuals (286 female, 383 male) aged 10-17 years performed the YBT-LQ with their left and right leg. Normalized maximal reach distances (% leg length) for all three directions (i.e., anterior, posterolateral, posteromedial) and the composite score were calculated. Further, age- and sex-specific percentile values (i.e., 10th to 90th percentile) were computed and plotted.
Results: In boys, the oldest age group (16-17 years) performed better than the younger ones (14-15, 12-13, and 10-11 years). In girls, the youngest age group (10-11 years) often achieved better values compared to the 12-13-year olds. Further, 16-17-year old boys compared to the same aged girls showed better YBT-LQ performance in all but one measure (except left leg reach in posterolateral direction). For both sexes, curvilinear shaped curves were detected for percentile values across the reach directions.
Conclusions: The generated age- and sex-specific reference values for the YBT-LQ can be used by practitioners to evaluate dynamic balance performance in healthy youth aged 10-17 years.
Competing Interests: Declaration of Competing Interest None of the authors has any conflicts of interest.
(Copyright © 2020 Elsevier B.V. All rights reserved.)