In some cases, the spinal disorder that causes low back pain can directly cause problems in the muscles in the back. Other times, low back pain leads to inactivity, which causes the muscles in the back to weaken and shrink. People who don't regain function in key muscles that steady the joints of the low back often end up with recurring back pain.
Exercise therapy has been shown to improve the health of these low back muscles. To fully recover from low back pain, it's important to start using those sore muscles again. Patients who do physical therapy, muscle training, and even low-impact aerobics may improve their back strength and endurance in as little as three months. Given enough time, exercise therapy may change the size and make-up of the muscles themselves, though this has yet to be proven.