Begin in a traditional plank position with both of your hands on the floor with your elbows and wrists in one line. Resting on the balls of your feet, brace your abdominals to maintain a neutral spine.
On an inhale, brace your abs, elevate your hips, and lift your left hand up off of the ground reaching toward your right foot. It's OK if your hand doesn't touch your foot.
On an exhale, lower back to the starting position. This counts as one rep. Repeat on the right side and continue to alternate between the right and left side.
Repeat for a total of 30 seconds, then take 30 seconds of rest.