Feeling like your SI joint all locked up? Give this a try and get some relief! Follow along with Craig in rolling your Posterior Superior Iliac Spine! My… what now?! Your PSIS! To do this exercise you’ll need a very firm foam roller. We recommend using on of our top 3 preferred rollers: the Vyper, the M80 or The Grid X. For more stretches, check out our extensive rehab video library. Now get rolling!