Chiropractic adjusments improve the ability to contract a stomach muscle called transversus abdominis, researchers say. The tranversus abdominus goes all the way around your trunk--from your low back all the way around to the front--much like a girdle. The significance of this muscle is that it gives a tremendous amount of support to the low back and pelvis. Weakness in this muscle group is a significant predictor of chronic low back pain. This study sheds more light as to why many people who have low back pain do not get better with an exercise program until they receive chiropractic care. By normalizing the function in the joints of the low back, chiropractic effectively "turns on" the muscles necessary for a healthy back! Link to the reference.