Single leg squat test as a clinical tool to predict lower extremity injuries in adolescent athletes

Abstract

Background: The single leg squat test (SLS) is a biomechanical evaluation, simple and easily performed, and has been validated against the gold standard of 3-Dimensional (D) motion analysis [1-3]. A positive SLS test used in frontal plane biomechanical analysis can indicate poor lower extremity mechanics, reduced core strength, or hip abductor weakness indicating a higher risk for lower extremity injury [4-8]. SLS test has been studied primarily with biomechanical outcomes, and there is limited injury data to assess its predictive value in adolescents. Objective: To determine the predictive value of SLS test in predicting lower extremity injuries in adolescent, high school athletes with prospective injury data collected by athletic trainers over a one year period. Design: Longitudinal, non-randomized prospective design. Setting: Clinical and field based. Interventions: 258 adolescent athletes from Central Oregon were evaluated while performing a SLS test during initial practices or during pre-participation physicals before the start of the academic year. Injuries sustained while playing sports during the following academic year were reported to each respective high school’s certified athletic trainer and recorded on the Sportsware database. Main Outcome Measurements: SLS Test and Injury Reports. Results: The sensitivity, specificity, and negative predictive value (NPV) of the SLS test in predicting lower extremity injuries were 66.67%, 36.59% and 95.74%, respectively. The sensitivity, specificity, and NPV of the SLS test in predicting a lower extremity injury in a high risk group of female soccer players were 50.00%, 30.16%, and 90.48%, respectively. Conclusion: Negative SLS in 36% of athletes was consistent with a low risk of lower extremity injury with 96% NPV. The high NPV is likely related to the low prevalence of LE injury in this study population and wouldn’t translate to higher prevalence LE injury populations. Further study is needed to determine clinical utility of the SLS test.