The lower part of the spine or the lumbar region is the region where most people experience back pain. This part of the back carries the weight of the body and the muscles are prone to strain.The diagram below illustrates the vertebrae of the spine.

Notice the 'S' shape of the spine, which I refer to later.

The lower back is acted upon by any of the muscles connected to the lower torso. For example, the abdominal muscles play a leading part in keeping the lower spine straight and any back exercise programme must strengthen the abdominals.  The subject of this article, however, is stretching the back of the legs or hamstring muscles and how that helps prevent or help treat lower back pain. It might not seem obviously necessary to stretch your legs in order to help your back, but let me explain why this is so.

The illustration of the leg muscles below gives us some idea of how the hamstring muscle is attached to the thigh bone (femur) at the bottom and the pelvis at the top.

Tight hamstrings tend to pull on the pelvis, as the top of the long hamstring is attached to the pelvis, so this causes a rounding of the lower back.

Over time, this postural imbalance will lead to back pain. Look at the following images.In the first image, the man has a normal S shape in his back.

 In the second image, the lower back is rounded, meaning that the hips have been pulled backwards by the hamstring. His back no longer has an S shape and is likely to suffer from lower back pain.

Stretching the hamstrings-a simple stretch

Sit on the ground with your right leg straight out in front of you. Bend your left leg, so that your left foot is close to your right leg. Bend forward at the hips and reach for your right shin or ankle. Pull gently. Hold the position for 30 seconds.

· Breathe. Don't hold your breath. Holding your breath can raise your blood pressure, if you do suffer from high blood pressure. In any event, it makes you more tense. The deeper you breathe, the more relaxed you are, the deeper and longer you will be able to stretch.

· Never force a stretch beyond the point of mild discomfort. Stretching tight muscles will be uncomfortable, but you should never feel any sharp or sudden pain. If you do, stop immediately-you are pushing yourself too far. Stretch the muscle at less of an angle eg in this exercise, don't pull the arm back as much.

· Be consistent. Stretching for a few minutes each day will gradually build flexibility and range of motion. This is far preferable to stretching only once a week for a longer time.

· Wear loose comfortable clothing. It's obviously very difficult to stretch if your clothes are tight and restrict movement.

· Time yourself and try to increase your time in each stretch by a few seconds each week. Start with 10-15 seconds and extend this by 5 seconds each week until you can hold a stretch for at least 30 seconds.

Andrew de Bruyn is the author of "Build your Back, Beat the Pain".