"Bird Dog" is an excellent exercise to help build hip, core, and scapular stability. Lower back pain is often caused by weak, de-conditioned spinal muscles or dysfunctional motor control. This exercise helps restore stability, muscle endurance and proper motor control to the areas which protect the spine during movement.
Here are a few tips on how to perform it correctly!
Begin in the quadruped position (on hands & knees) with knees under hips, hands under shoulders
Create an abdominal brace by stiffening the abs and trunk muscles (imagine bracing for a punch to the stomach)
Maintain a natural or neutral spine, make sure not to hyperextend the head and neck
Slowly extend the opposite arm and leg, pressing the heel straight back, making a fist
Hold for 5-10 seconds
Return to start position and perform with the opposite arm and legPerform 3 sets of 10 repetitions total.