QL stretch & abdominal oblique- spine rotation

spinal rotation and flexion are contraindicated for me.  esther's QL stretch class on 1/13 involved a 'convex curve over arching stretch' and her abdominal oblique class yesterday involved 'twist and untwist' lower spine.  i absolutely love this program, and i wonder with these rotation recommendations, is there an alternative way to exercise those muscles without rotation?  or, once i learn how to be tall and engage abs, will it be safe?  thanks so much ;-)