The cat-cow exercise strengthens your belly (abdominal) muscles and improves spinal flexibility. Follow these steps to do a cat-cow:

• Kneel on a mat (exercise, yoga) or floor on your hands and knees. Keep your knees under your hips and your wrists under your shoulders. Keep your back straight and your neck in its natural position.
• Press your back upward by tightening the muscles of your belly and buttocks. The top of your back will be rounded and your belly area will be tight. (Imagine a cat with its back arched "up.") Hold this cat position for 10 to 15 seconds.
• Slowly relax and let your belly fall toward the floor (cow position). This will increase the arch of your lower back. Next, allow your shoulder blades to fall together toward your spine. Hold this position for 10 to 15 seconds. Return to starting position. Repeat the exercise 5 times.