The Knee to Chest Stretch is for the small muscles in the low back that surround the spine.
This stretch is done while lying on your back. With the knees bent so the feet are flat on the floor, bring one knee toward your chest by holding onto the leg just below the knee. Pull the knee toward the chest with your arms. This should stretch the low back. Switch to the other leg and repeat. Then, pull both knees to the chest at the same time.
This is best done first thing in the morning and before bed.
Hold each stretch for 20-30 seconds, 2-3 times. Repeat at least 2 times per day.
*If you have knee problems, grab the legs around the thigh (behind the knee) to avoid injuring the knees.