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, 18-29 y).
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 degrees +/-2.3 degrees from a horizontal reference, and for women it was 36.9 degrees +/-3.4 degrees . A significant difference was found between men and women on performance of the DLLT (t 98 = -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.