The Reliability and Discriminative Ability of the Overhead Squat Test for Observational Screening of Medial Knee Displacement

Abstract

CONTEXT: The overhead squat test (OHS) is a functional screening exam that is used to identify high-risk movement profiles such as medial knee displacement (MKD). The reliability and discriminative ability of observational screening during the OHS to identify MKD have yet to be established. OBJECTIVE: To investigate the reliability and discriminative ability of observational screening for medial knee displacement MKD during the OHS. STUDY DESIGN: Clinical measurement, cross sectional. PARTICIPANTS: 100 college students were video-recorded performing the OHS. Three certified athletic trainers classified the knee posture of each subject during the OHS on 2 different occasions using screening guidelines. MAIN OUTCOME MEASURES: Ratings were evaluated by calculating kappa coefficients for intra- and interrater levels of agreements. MKD was measured using motion analysis. RESULTS: Intrarater reliability ranged from .60-.76 with an average value of .70. Interrater reliability was substantial (kappa > .60) for both observation sessions (Fleiss kappa session 1 = .69, session 2 = .70). Sensitivity ranged was .58-.83, while specificity ranged was .70-.88. The MKD group displayed significantly more displacement than the no-MKD group (p < .001). There was a moderate positive correlation (r = .48, p < .001) between knee-posture group and MKD assessed using motion analysis. CONCLUSION: The OHS has substantial reliability and is able to assess the presence of MKD. The OHS should be used as part of a comprehensive examination that evaluates multiple movement patterns and risk levels.