The Bird Dog exercise is a core strengthening move that also engages the lower back and glutes. Begin on all fours with your hands directly under your shoulders and knees under your hips. Extend your right arm forward and your left leg back, keeping both parallel to the floor. Hold for a moment, then return to the starting position and switch sides. Maintain a neutral spine throughout the movement, engaging your core to prevent any arching or sagging of the back.