Kneel on the floor and put your hands on the floor in front of you. Keep your hands shoulder-width apart and your knees directly below your hips. Inhale deeply while curving your lower back and bringing your head up, tilting your pelvis up like a "cow." Exhale deeply and bring your abdomen in, arching your spine and bringing your head and pelvis down like a "cat." Repeat several times.
If you have injuries or if you're concerned about exercising, consult with your health care provider before starting a yoga program.