Near two years ago I got a back injury, which did not yield to the chiropractor, so I went to my doc, who sent me to physical therapy. I saw two therapists, which helped, although one of them said "I think you may have an injured disc, but perhaps not. I think it is possible that you may return to health as you knew it." Well, I got various exercises, which helped the back, some Pilates, and various calisthenics and funny exercises. My upper abdomen responds, but my lower abdomen, I find it tougher going to achieve good tone. THe one physical therapist said that I needed to learn body control, which is sensible, and prescribed situps, only if I did not anchor my feet. I didn't think with my heavier torso I could do that, but I can do them, she was correct about that, and I suppose it helps the lower abdomen some. She didn't think leg raises were good (for my back) then. She said my iliopsoas muscles were all tight. However, now things are better, after her treatment, and if I keep up with the back exercises, and with stretches. She gave me what I call the Cyndi Lauper exercise, which is sort of a standing alternating crunch, quite strange looking as are many useful exercises. As you obtain more awareness of the lower abdomen muscles, they come into better fettle, she assures me.
In George Jowett's book he recommends alternating leg raises, or two legged leg raises, for the lower abdomen, for one. I started to do them, which does help, as well as a scissors movement. I also pulled a groin muscle again as I got hooked by a heavy plank that I was unloading, but after rest and hopefully judicious exercise, that is improving. He was an observant student of anatomy, it seems to me. However, Stuart McRobert considers that all leg raises and situps, except for a crunch style, in which the lower back remains on the floor, all exercise the hip flexors, the iliopsoas muscles, and so tightness may pull on the back. I had this going on when I saw the physical therapist, which she helped with a treatment she learned.
To put it shortly, I would like to hear ideas on useful exercises for the lower abdomen.