When you can hold the standard Plank for more than 60 seconds, this is a great progression to try. The Superman Plank starts off with your arms extended about 45 degrees in front of you and on your palms rather than your forearms. All the same rules of the Plank apply, but you'll find yourself holding the Superman Plank for a much shorter time — start off with 15 seconds, ensuring that your lower back is neutral at all times. If you feel your hips start to sag, it's time to stop that rep. Work up to hold for as long as possible. If you can reach 60 seconds, you deserve superhero status!