Hi.

Try a load-transfer test (out of interest).

ASLR (Active Straight-Leg Raise) Test
1. Lie Supine
2. Lift one leg and note it's heaviness, the ease of action and whether your pelvis rolls. If you want to be really tricky, try to feel the obliques and TrAbs as well.
3. Lift the other leg and note the same.
4. Does one leg feel different to the other? If not, then the test is negative. If so, continue...
5. Try to compress (or have someone else compress) the p.symph (then re-assess by lifting that leg noting the above), PSIS (re-assess), ASIS (re-assess) and G.Trochanters (re-assess).

If any of these make lifting the leg easier, you may have a load transfer problem including muscle inhibition. If any of the above make it harder, you may have hypertonic muscles compressing your Wikipedia reference-linkSIJ.

Just out of interest of course...

BTW, how do you know that the SIJ is not dysfunctional?
ITBFS is often due to a hypertonic TFL and inhibited Glut med - has that been addressed in the past?