Alsalaheen B.1, Yorke A.1, Smith L.1
1University of Michigan, Physical Therapy, Flint, United States
Background: The majority of the dynamic balance tests assess the spatial components of dynamic balance such as sway or excursion. While postural sway and excursion are important components in dynamic balance, they do not reflect the neurodynamic aspects of dynamic balance. Since most injuries are attributed to increased spatial demands in a relatively short time, a validated measure of dynamic balance such as the Limits of Stability (LOS) test that quantifies the spatial and temporal aspects of balance is important in the realm of injury prevention and rehabilitation. However, the relationship among the LOS metrics is unclear and the reference values in adolescents have not been documented. Previous research has indicated that male and female adolescents may have different balance strategies that may contribute to the differential rate of injuries. Additionally, previous research has indicated a possible negative effect of increased body mass on postural stability, and increasing the risks for injuries for individuals with heavier body mass. Yet, the effect of gender and body mass on the performance of LOS is unclear.
Purpose: This study aims to report preliminary reference values for the LOS test in adolescents, examine the relationship between LOS scores to gender and body mass, and to explore the relationships among the LOS test metrics.
Methods: A cross sectional observational study of two hundred and one participants who completed the LOS test at 100% of the theoretical limit. The reaction time, movement velocity, endpoint excursion, maximum excursion and the directional control were computed. The relationships among the LOS between the LOS scores and body mass were explored using Spearman Rho correlation coefficient. Additionally, the effect of gender on the LOS scores was examined using Mann-Whitney U test. The reference values of the LOS test scores were reported using percentile scores between the 5th and the 95th percentile.
Results: Female participants demonstrated faster movement velocity, but less directional control compared to male participants. Additionally, heavier body mass was associated with less endpoint excursion. Amongst the limits of stability composite scores, a significant relationship between reaction time (|rs|:0.18-0.46), maximum excursion (|rs|:0.15-0.82), endpoint excursion (|rs|:0.21-0.82), movement velocity (|rs|:0.15 -0.46), and directional control (|rs|:0.35-0.39) was observed.
Conclusion(s): Male and female adolescents may employ a slightly different balance strategy. The LOS composite scores measure related but not identical aspects of dynamic balance. The reference values presented in this study may assist clinicians in identifying balance impairments in adolescent presenting with balance problems.
Implications: These findings highlight the importance of concurrent assessment of spatial and temporal characteristics to accurately reflect the complex nature of dynamic balance. As indicated by the presented reference values, adolescents demonstrated variations in LOS performance. Therefore, a baseline comparison is ideal to document the effects of injuries and to track rehabilitation outcomes. In the absence of baseline score, the reference values provide age-validated benchmarks for the LOS test in adolescents. The reference values presented in this study may assist clinicians in identifying balance impairments in adolescents presenting with balance problems.
Funding acknowledgements: Dr. Ben F. Bryer Foundation Medical Research Fund, and by the University of Michigan-Flint's Research and Creative Activity (RCA) Award
Topic: Paediatrics
Ethics approval: This project was approved by the Institutional Review Board at University of Michigan-Flint.
All authors, affiliations and abstracts have been published as submitted.
