This exercise is especially beneficial for the digestive system. Sit with your head, neck, and trunk straight, and your legs stretched in front of your body. When inhaling, raise your arms overhead, stretching toward the sky and expanding the chest as your breath fills your lungs. When exhaling, bend forward as far as possible while keeping your back straight and your knees on the floor; hold this position for 5 to 10 seconds. To be effective, this exercise should be repeated 20 or more times.