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.