Criterion-related validity of sit-and-reach tests in university men in Hong Kong.

To examine the criterion-related validity of traditional, modified, and YMCA sit-and-reach tests and the relationships of these with abdominal muscular strength and endurance measured by the sit-up test, 52 university men of mean age 20.7 yr. were administered two trials of six measurements in counterbalanced order, including traditional, modified, and YMCA sit-and-reach tests, passive straight-leg raise, low-back flexibility evaluation, and 1-min. sit-up test. Pearson product-moment correlations were significant (p < .05) for traditional and modified sit-and-reach tests with hamstrings' flexibility (rs = .71 and .77, respectively). Also, the YMCA sit-and-reach test was significantly associated with hamstrings' flexibility (r = .64) and low-back flexibility (r = .47). Stepwise multiple regression indicated hamstrings' flexibility was the only significant predictor of traditional and modified sit-and-reach tests, explaining the variances of 59.1% and 49.8%, respectively. However, both hamstring and low-back flexibility were significant predictors for the YMCA sit-and-reach test, which in total accounted for 52.2% of explained variance. Traditional and modified sit-and-reach tests are valid in assessing hamstrings' flexibility only, whereas the YMCA sit-and-reach test is valid for measuring both the hamstring and low-back flexibility.