It likely doesn't matter which type of therapy you choose. A recent study found that patients with low back pain benefited from several kinds of exercise therapy. Some of the patients who participated in the study had physical therapy. Some had muscle training with special devices. And some took an aerobics and stretching class. After three months of therapy, patients in all groups were better able to do their regular activities, no matter which kind of exercise therapy they had.
Ask your doctor what type of exercise therapy he or she would recommend. And make sure to choose a kind of therapy you enjoy. The more you like your program, the more likely you are to stick with it and reap the benefits.