According to Peggy Brill, author of "The Core Program: 15 minutes a day that will change your health," one cause of incontinence can be doing the wrong ab exercises. She says that most crunch exercises put too much strain on the rectus abdominus, and that core exercises (like "dead bugs," or plank position, and several others she shows) can better strengthen the abs (especially the often neglected transverse abdominals that can lead to lower belly pooch). Since I'm one of those "does-ab-crunches-till-they-hurt-but-still-has-a-lower-ab-pooch people, I've incorporated in my routine more of the kinds of exercises she shows in place of crunches. I haven't been regular enough with them yet (or with my workouts in general) to see a difference, but I can feel the work in my abs in a different way. One thing I like to do is bicycles (which rely more on core stabilization than on actually crunching). I like the ab section at the end of Power Hour (though I sub dead bugs, lower ab lifts and extra bicycles for the beginning crunches).