The yoga position called downward facing dog is a great position to correct posture and to keep your back chain mobile from head to toes.
But for most people, it is uncomfortable painful or not recommended depending on your medical condition. By using a table at begin with, you can get the benefit of the pose while controlling the stretch better. Listen to your body, let your chest open, your hip roll until you feel your hamstrings (the back of your legs). Practice at your own speed and intensity. You should feel the stretch but it should not hurt too much.
Try to practice every day and see your progress by taking a picture of you on day 1 and 10. Let me know how you went! If this is too easy, then use a chair (against the wall) and progress to the floor when ready if you don't have any contraindication.