Relation Between Subjective and Objective Scores on the Active Straight Leg Raising Test

Cross sectional. To fill a gap in the validation of the active straight leg raising (ASLR) test concerning the relation between a patient's subjective score on the ASLR test and the objective measured force. The ASLR test is used to classify patients presenting with pain in the low back and/or pelvic girdle. Although its reliability and validity have been demonstrated, some details are still lacking. The ASLR test was performed by 21 parous women with various ASLR scores. Subjective weakness was scored by the patient both with and without a pelvic belt; moreover the isometric forces of leg raising were measured. The correlation coefficients between the subjective ASLR score and objective measured force at 0 and 20 cm elevation were -0.58 (P < 0.01) and -0.52 (P < 0.05), respectively, at the left side; and -0.45 (P < 0.05) and -0.63 (P < 0.01), respectively, at the right side. When measured with a pelvic belt the correlations were, respectively, -0.51 and -0.48 at the left side, and -0.47 and -0.50 at the right side (all P < 0.05). After applying a pelvic belt the mean subjective ASLR score decreased with 0.38 point at the left side and 0.48 point at the right side (both P < 0.05). With the belt, the measured force at 0 cm elevation increased by 11.6% (P < 0.001) at the left side and by 8.6% (P < 0.05) at the right side; at 20 cm elevation the changes in measured force were negligible. No significant correlation was found between the subjective and the objective changes elicited by the pelvic belt. The subjective scores on the ASLR test correlate well with the objective measured forces; this supports the reliability of the ASLR test. The subjective influence of a pelvic belt on the ASLR score could not be objectified.