Influence of hip position on measurements of the straight leg raise test.

Abstract

Variations of the straight leg raise (SLR) test are described clinically; however, no studies have examined how these variations may affect the outcome of this test. This study examined whether measurements of SLR are influenced by position of contralateral hip (flexed vs. extended), nature of the trial (active vs. passive), or trial repetitions (1 vs. 2). Twenty-two healthy, young subjects participated in this study. A 35-mm camera recorded the position of the pelvis and lower limb during the performance of a right SLR. Passive SLR (opposite hip extended vs. opposite hip flexed) and active SLR (opposite hip extended vs. opposite hip flexed) were performed twice, in random order. Three different measures of SLR were obtained while subjects performed SLR under the aforementioned conditions--SLR relative to horizontal, SLR relative to pelvis, and pelvis relative to horizontal. Differences in SLR between opposite hip flexed vs. extended, passive vs. active, and trials were analyzed using a multifactorial analysis of variance for repeated measures. Hip position affected SLR relative to horizontal (p < .000) and pelvis relative to horizontal (p < .000), with an increase in measurement occurring with the opposite hip flexed. Nature of the trial (active vs. passive) affected SLR to pelvis (p < .003) and pelvis to horizontal (p < .000) with an increase in measurement for passive SLR. A difference in measurements existed between trials 1 and 2 for SLR to horizontal (p < .005) and for SLR to pelvis (p < .005). Although conducted on healthy subjects, the study points out the necessity of consistency of method when performing and interpreting the SLR test.