Most lower back pain results from strained muscles or ligaments, and though often painful, usually resolves on its own. Structural problems in the spine, such as herniated discs, sometimes require surgical intervention. Swimming provides a nonweight-bearing environment in which to exercise the large muscles in the back and the smaller muscle groups that help support them. Proper stroke technique prevents swimming-related injuries, and stroke drills and kicks help relieve tense muscles.
Swimming works out the large muscles in the chest, back, and the legs. Overuse or weakness of muscles used to rotate your body in freestyle leads to lower back pain. Pulling freestyle means swimming with your legs isolated trailing behind. It changes the swimmer’s position in the water somewhat, and eliminates any painful movements associated with the flutter kick. Using a pull buoy keeps legs from sinking and helps keeps the body high in the water. Keep a streamlined position and your head steady. Take long strokes, counting the strokes per length. Pull four laps of a 50 m pool, or eight laps of a 25 m pool. Reduce the number of strokes per length and concentrate on elongating your body and stretching out the muscles in your lower back.
Vertical kicking forces the swimmer to maintain balance in the water and to use leg and supporting abdominal muscles to keep upright. Perform a flutter or freestyle kick, keeping your arms out of the water in a “surrender” position. Kick for one minute. Then, keep legs still and scull with your hands to keep on top of the water. Sculling means making continuous circular movements with the hands, palms face down on the water. Bring your knees up and extend your feet so that the legs are perpendicular to your torso. Hold the position for a moment, then continue.
Repeat for one minute.
Turn onto your back and perform dolphin kicks, pulling and pushing using the core muscles in your abdomen. Use an undulating hip motion to flex and contract back muscles. Repeat with and without swim fins. Do the similar exercise while on the side. Only do the dolphin kick sets when your lower back is healthy and pain free.
Source: www.livestrong.com; Barrett Barlowe; June 14, 2011.