Several indirect clinical tests for measuring hamstring muscle length are available, but the
influence of their test procedures is not well documented. This study examined four of these tests to
clarify the results relative to the testing procedures. The right limbs of 30 men were tested for: I)
passive straight leg raise (SLR) with the pelvis and opposite thigh stabilized with straps (SLR-$5); 2)
passive SIR with the low back flat and, if needed, the opposite thigh slightly flexed and supported
on pillows (SLR-LBF); 3) active knee extension with the hip at 90" (AKE); and 4) passive knee
extension with the hip at 90" (PKE). A dependent t-test showed no significant differences between
the angles oi SLR-55 (61" + 6.7") and SIR-LBF (62" f 6.2'')). The SIR-SS and SIR-LBF angles for
subjects needing pillows under the opposite thigh for the SIR-LBF test fN = 18) also were not
significantly different. The knee flexion angles for the AKE (43" f 10.2") and the PKE (3 1" f 7.57
tests were significantly different (p < 0.001). Significant relationships (Pearson r) were found among
the four tests (p < 0.05). The similar angles for SLR-SS and SIR-LBF and their significant relationship
(r = 0.70, p < 0.001) indicated that their different testing procedures probably h;ld a minimal
influence on test results. The difference between the AKE and PKE tests suggested that ihe AKE test
and the PKE test may represent an "initial length" and a "maximal length," respectively. These
results should help clinicians apply the tests appropriately and interpret the results accurately.