Lying Knee-to-Chest Stretch
This one reaches your quads, hip flexors, lower back, and hamstrings. Lie on your back and gently pull one knee toward your chest until you feel a stretch in your lower back. Leave the other leg bent if you have low back pain. Otherwise, choose what's more comfortable. If straight, you can add to the stretch by pushing the back of your knee toward the floor. Hold it for 30 seconds and then switch legs.