Another way to improve or maintain your lumbar mobility is the sidelying lumbar rotation stretch. Lie on your back and bring one knee across your body so that your feel a gentle twist in your lower back and a slight stretch in the outside of the hip.
Like any stretch, you will get the most benefit if you hold it for longer than 30 seconds.
This is another great way to allow the spine to move without placing much load on it. It is effective in reducing stiffness in both the spine and hips and helping to give your spine healthy, stress-free motion.