Leg Dominance Effects During Single- and Dual-Task Modified Balance Error Scoring System Assessment in Collegiate and High School Athletes.

Background: The modified Balance Error Scoring System (mBESS) incorporates nondominant leg stance for a ceiling effect, but that may not be the worse balancing leg. Updated recommendations call for single- and dual-task tandem gait, but limited research has explored these effects on the mBESS.

Purposes: To compare mBESS performance between dominant and nondominant legs during single and dual tasks and to determine 1-week test-retest reliability.

Study design: Cross-sectional study; Level of evidence, 3.

Methods: A total of 119 intercollegiate, collegiate club, and high school athletes were administered a baseline mBESS battery consisting of performance on both legs and during single and dual task at 2 time points, 1 week apart. Measures consisted of mBESS errors and sway index during counterbalanced single- and dual-task conditions on dominant and nondominant legs. Wilcoxon signed-rank tests were conducted to determine differences in errors and sway index between dominant and nondominant legs and single- and dual-task performance. Spearman correlations were used to measure reliability at 1 week ± 2 days.

Results: No differences were observed between nondominant and dominant single-leg errors (P = .79) and sway index (P = .98), nor tandem stance errors (P = .95) and sway index (P = .86). Greater errors were committed during dual-task single-leg stance (P = .05) but not on sway index (P = .69). No differences existed between single and dual tasks on tandem errors (P = .63) and sway index (P = .53). Test-retest coefficients were weak to moderate (r_s = -0.009 to 0.368) for normal mBESS errors and fair for sway index (r_s = 0.389 to 0.442) at a 1-week interval.

Conclusion: Our study demonstrated that leg dominance does not appear to affect mBESS errors or sway index, indicating that either leg may be used, in the absence of lower extremity injury history or instability. Incorporation of a dual task provides little clinical utility and may not be specific enough to elicit postural control changes on the mBESS, further indicating the use of optional foam conditions or single- and dual-task tandem gait. Caution is needed when using mBESS after a 1-week time point.