Lie flat on your back on an exercise mat with your knees bent and feet placed firmly on the floor, shoulder width apart. Keeping your core braced, lift your hips slightly and place a foam roller perpendicular to your body under the base of your spine. Proceed to gently lift both feet from the floor, hugging you knees in towards your chest. This is your start position. Slowly and with control, make small circular motions with your knees, feeling for any particular areas of tension in your lumbar spine. Repeat for the recommended amount of time.