Begin on your hands and knees, making sure your wrists are directly below your shoulders and your knees are directly below your hips. Your spine should be neutral, with the back of your head aligned with your shoulder blades. Maintaining this alignment, slowly lift one leg and the opposite arm until they are aligned with your spine, then lower back toward the floor. Avoid arching or twisting your back during this exercise. Alternate for a total of 5x on each side.