Get on your hands and knees, with your palms flat on the floor lined below your shoulders, and your hips situated directly above your knees. Inhale a deep breath, and while doing so gently round your back, so it rises toward the ceiling. Hold this stretch for about ten seconds. Then give a long exhale, while doing so gently arch your back toward the floor, so it is your tailbone and chest that is stretching toward the ceiling. Again, hold the position for about ten seconds. Slowly alternate this stretch of your spine for five repetitions.