Come into a plank position with your hands underneath your shoulders and your feet a little wider than hip-distance apart. Engage your core and lower-body muscles by pulling your belly button into your spine and contracting your glutes and quads.
With control, lift your right hand off the ground and lift it straight behind you, fully extending your arm with your palm facing up. Make sure to keep your back flat and avoiding shifting your hips. Both hips should be pointing down toward the ground.
Pulse your arm up an inch, contracting through your triceps. Then lower your arm back to the starting position.
The wider your feet are, the easier it will be to stabilize your body. If performing this move from the plank position is too challenging, you can modify this movement by lowering down to your knees. Be sure to keep your hips fully extended throughout the movement.