The reliability of the modified balance error scoring system

Objective: Study 1 investigated the intraclass reliability and percent variance associated with each component within the traditional Balance Error Scoring System (BESS) protocol. Study 2 investigated the reliability of subsequent modifications of the BESS. Design: Prospective cross-sectional examination of the traditional and modified BESS protocols. Setting: Schools participating in Georgia High School Athletics Association. Intervention: The modified BESS consisted of 2 surfaces (firm and foam) and 2 stances (single-leg and tandem-leg stance) repeated for a total of three 20-second trials. Participants: Participants consisted of 2 independent samples of high school athletes aged 13 to 19 years. Main Outcome Measures: Percent variance for each condition of the BESS was obtained using GENOVA 3.1. An intraclass reliability coefficient and repeated measures analysis of variance were calculated using SPSS 13.0. Results: Study 1 obtained an intraclass correlation coefficient (r = 0.60) with stance accounting for 55% of the total variance. Removing the double-leg stance increased the intraclass correlation coefficient (r = 0.71). Study 2 found a statistically significant difference between trials 1 and 2 (F(1.65,286) = 4.890, P = 0.013) and intraclass reliability coefficient of r = 0.88 for 3 trials of 4 conditions. Conclusions: The variance associated with the double-leg stance was very small, and when removed, the intraclass reliability coefficient of the BESS increased. Removal of the double-leg stance and addition of 3 trials of 4 conditions provided an easily administered, cost-effective, time-efficient tool that provides reliable objective information for clinicians to base clinical decisions upon.