caption: Slide 2 of 7: Start resting on all fours. With your palms flat, raise up off your knees onto your toes. Keep your hands directly below your shoulders. Contract your abs to keep yourself up and prevent your bottom from sticking up. Remember to keep your belly button pulled in. With your head and spine in line, keep your back flat - don't let it curve. Picture your body as a long, straight board. Hold for 30 seconds.