My favorite ab worker so far is the bicycle crunch but it doesn't feel good after a while because of my anterior pelvic tilt. Having all that space between the arch of my back and the floor just doesn't feel right. I also tried doing leg lifts but there was a small clicking sound in my back when I brought my legs down and I figured that was unnatural so decided not to do those. I'm looking for some recommendations of a good ab workout that is easy on the lower back.