Abdominal muscle performance as measured by the double leg-lowering test

Objective: To describe abdominal muscle performance as measured by the double leg-lowering test (DLLT) in healthy subjects. Design: Repeated measures. Setting: Academic laboratory. Participants: A sample of 100 healthy volunteers (50 men, 50 women; age range, 18-29y). Interventions: Not applicable. Main Outcome Measures: Repeat measurements of the DLLT to determine reliability and performance standards and to identify variables that predict performance. Results: The intraclass correlation coefficient (ICC_3,1) for repeated measures of the DLLT was .98. The mean value ± standard error of the mean for abdominal performance for men was 15.4°±2.3° from a horizontal reference, and for women it was 36.9°±3.4°. A significant difference was found between men and women on performance of the DLLT (t₉₈=-5.3, P<.001). A linear regression model found sex (t=-3.2, P=.002) and age (t=-4.6, P<.001) to be significant predictors of performance on the DLLT. Conclusions: The DLLT has excellent intratester reliability. We also found a sex difference in the performance of the DLLT.