Lie flat on the back, with the hands resting at the sides. Tense all the muscles throughout the body and press it against the floor as hard as you can. By drawing in the abdominal wall and contracting the abdominal muscles, the lower spine can be more flattened against the floor. Try to bring as much of your back in contact with the floor as possible. When tired, rest. Repeat the rhythm of pressure and rest five times. Variation (a) Perform the same exercise but raise both feet six inches in the air, still tensing their muscles. When tired, rest. Repeat three times. Variation (b) Sit on hard chair, hands on hips, feet flat on floor. Straighten the lower back curve by contracting the abdominal and gluteal muscles, the pelvis will then be held at the proper angle, the trunk will be at a right angle to the thighs. Then relax these muscles. These exercises invigorate the whole body in a very short time and force the breath to deepen itself. They straighten the lower back curve.
-- Notebooks Category 5: The Body > Chapter 5: Exercise > # 130