Start in a high plank position with your legs wider than hip-width apart; the wider stance makes you more stable. Hold a dumbbell in each hand, keeping your wrists directly below your shoulders and locking them to protect the joint.
With your core tight and your glutes squeezed, exhale, stabilizing your torso as you bend your left elbow up toward the ceiling and lift the dumbbell up to your armpit. You should feel your left shoulder blade sliding toward your spine as you move. Keep your core pulled toward your spine and your glutes squeezed throughout the movement.
Keeping your neck in line with your spine, lower the dumbbell to the ground with control. Avoid rocking your torso throughout as you lift and lower the weight.
Repeat the movement on your right side.
This completes one rep. Complete as many reps as you can with proper form in 20 seconds.