Lie on your back with your knees bent and your feet flat on the floor. Tighten your buttocks and lift your hips off the floor. Tighten your abdominal muscles and lift one foot a couple of inches off the floor. Then put it down and lift the other foot a couple of inches, all while remembering to breathe. “It’s like taking alternate steps,” Pariser says. Work up to doing 30 steps at a time.