I have terrible back pain. I took the Crush your Core 1 program and I've picked out a few of her 10 minute workouts that I can do. I did the whole 4 weeks and when there were exercises that put too much strain on my back, I would make adjustments. I bookmarked the days that I can do with little pain.Hi, has anyone found a good 10 minute core exercise routine that doesn't put any stress on your lower back? Thanks.