One that I do is called bridging, that is one that I have found on-line. It engages the same muscles as a sit-up, but is easier on your lower back. Another one is squats. With a chair behind you(preferably with arm rests), you stand up and flex your legs down. You do not have any wieght on your shoulders. The physical therapists were working my good side and my bad side equally, they did not want one side getting bigger than the other. I also have found that the bad side wants to mimic the good side. The body has tons of redundacies just for this reason. When one muscle group shuts down, another is right behind it. You do have to train it to work. I had a physically demanding job not to long ago so my MS could not be seen because my muscles were strong. If you give up, you could lose your ability to walk. I am going to have this for the rest of my life and I am going to have to exercise for the rest of my life.