This ab move is extremely challenging, so it's no wonder Anna incorporated a variation of it into her arm and core workout.
- Start face down on the floor, resting on your forearms and knees.
- Push off the floor, raising up off your knees onto your toes and resting mainly on your elbows.
- Contract your abdominals to keep yourself up and prevent your booty from sticking up.
- Keep your back flat — don't let it droop or you'll be defeating the purpose. Picture your body as a long straight board, or plank.
- With a flat back, use your elbows to pull your body forward, then come back to your starting position. Be sure to keep your neck and spine in a neutral position. This completes one rep.