Take the core-strengthening plank up a notch with this move that also involves the obliques and upper back.
1. Lie on your stomach and fold both forearms in front of your chest so that they are parallel with the top edge of the mat.
2. Lift your body into a plank position (like you did for toe taps), but keep your forearms on the mat.
3. Shift your weight onto your left forearm as you open your body toward the right side of the mat. Your right foot should come slightly in front of the left as you drive the right elbow up and back.
4. Slowly come back to center with both forearms on the ground.
5. Repeat the movement on the opposite side.
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