A Comparison of Two Isometric Tests of Trunk Flexor Endurance

This study was performed to determine the test-retest reliability and the relationship between 2 tests of trunk flexor muscular endurance-a prone bridge and a modified V-sit. Hold times (in seconds) were measured on 60 healthy volunteers from a University community (17 men, 43 women). Both tests were performed at 1-week intervals. The test-retest reliability of each test was assessed with a subgroup of 10 participants during 3 additional testing sessions at 1-week intervals. One examiner collected all data. Intraclass correlation coefficients (2, 1) with the prone bridge were 0.95 and 0.71 with the modified V-sit. The mean hold time was 92.8 ± 44.4 seconds during the prone bridge and 141.7 ± 104.1 seconds during the modified V-sit. Pearson's correlation coefficients between the 2 tests ranged from r = 0.52 (men + women) to r = 0.87 (men only). Intersession reliability with a single examiner was higher with the prone bridge compared with that in the modified V-sit. Modifications to the V-sit resulted in a lower test-retest reliability than was previously reported. Correlations between prone bridge and modified V-sit test scores were low, which may be attributable to the differences in the level of trunk flexor muscle activation between the tests.