“ASLR with or without ‘reinforcement’ (pelvic compression) to engage the form & force closure can be used to evaluate a patients’ ability to transfer load from the LS junction thru the pelvic girdle and hip joint to the lower extremity. A (right) supine ALR results in:
PI rotation of right innominate, anterior rotation of sacral base with nutation of right SI.
A tendency for the whole pelvis to rotate around the vertical axis toward the raised leg as well as a rotation at the LS junction in the opposite direction which decreases SI joint motion.
The overall effect is a stabilization of both LS and (in this case) right SI joint. A decreased ability to perform the ASL test while supine seems to correlate with abnormally increased mobility of the pelvic girdle. If dysfunction is found it can be assessed as to whether the problem is with the active or passive restraint systems. If contraction of the “inner core” (e.g. TrA, pelvic floor etc contraction) stabilizes and improves ROM and symmetry of leg-raise the clinician can focus there…If the anterior oblique system (tested via restraint of opposite trunk rotation) is at issue then that area can be addressed. The Posterior oblique system can be better evaluated via the prone ALR challenge”.