Many computer users around the world face the problem of back pain. Having your back against the wall usually means you're in trouble. But for certain yoga positions, having your back firmly against a wall will aid health. In Hatha Yoga, the practitioner forms what Swami Gitananda calls body geometry--triangles, straight lines, circles and parallel lines. When you do a posture, always stretch your body to its utmost limit and then hold it there for a slow count of 10, gradually building up the time, until each posture can be maintained for 30 seconds. Holding a posture is essential to yoga because it gives the body a chance to settle into the stretch and loosen up. Then each time you stretch it will be just that little bit farther. Many of the sideways, or lateral, stretches in Hatha Yoga require that the body face forward, with hips level and back and spine tilting neither forward nor back. Beginners tend to lean forward to increase the stretch. But leaning forward is wrong and will actually detract from benefits and possibly cause harm. To perform these stretches properly, make sure to keep your spine firmly against a wall. The wall acts as a prop. Even those who have practiced yoga may find that they cannot bend as far as they thought they could when they do the postures properly. The extra time spent in forming careful postures will pay off: Your body will gain excellent flexibility and strength.