From Healthwise
Exercise and staying active may relieve low back pain and can help speed your recovery.2, 3 Stretching and strengthening your stomach, back, and leg muscles helps make them less susceptible to injury that can cause back pain. Strong stomach, back, and leg muscles also better support your spine, reducing pressure on your spinal discs. This may help prevent disc injury.
Aerobic exercises—such as walking, swimming, or walking in waist-deep water—also help you maintain a healthy back. Aerobic exercise makes your heart and other muscles use oxygen more efficiently. Muscles that frequently receive oxygen-rich blood stay healthier.