Measurement of the Load on the Posterior Superior Iliac Spines during the SLR Test

Abstract

[Purpose] The purpose of this study was to simultaneously measure the passive Straight Leg Raising (SLR) angle and the load on the posterior superior iliac spines (pelvic load), and analyze their relationship. [Subjects] Twenty healthy students volunteered for this study (age 18-24 years, 10 males and 10 females). [Methods] All measurements were performed on a measuring plate incorporating a load measuring device attached to a strain sensor. The SLR angle and the pelvic load were measured simultaneously. The pelvic load was measured for 3 seconds at each angle of passive SLR, raised in increments of 5 degrees. The ratio of pelvic load divided by body weight (pelvic load ratio) was calculated. [Results] The SLR angle positively correlated with the pelvic load ratio in all subjects. A positive correlation was found between the maximum SLR angle and the maximum pelvic load ratio (r=0.68). [Conclusion] The SLR angle positively correlated with pelvic load in all subjects. This result suggests that pelvic load during SLR reflects pelvic retroversion to some extent.