If you want more of a challenge, do this exercise with a dumbbell or medicine ball — you'll definitely feel the burn.
- "Start by sitting on your butt and leaning back until you feel your abs engage. (Important: keep your feet pinned to the ground! This will help make sure your core is engaged," Garzo explained.)
- "Reach down to one side with both hands (or weight, if you're using one) then rotate up to the opposite side as if you were drawing a diagonal line from your hip to the sky," she said.
- Do 15-20 reps on each side.