A lot of my low back patients tell me that they have tried to stretch their backs out by bending forward to touch their toes. Unfortunately, this is not a good stretch for most of them. So how should you stretch out your back if it feels tight or stiff?
Here is a simple exercise that you can do this weekend at home, either on your bed, on the couch or on the floor. Lie on your tummy (face-down), and prop up onto your forearms. Hold this position for a few minutes as you watch AFV, play Angry Birds or read the paper. This is a position that children stay in sometimes when they watch TV or play video games, but it actually is a very healthy position for adults as well! Think about the position that your low back is in throughout most of your day. How often, if ever, do you stretch your spine in the backwards direction? The forward position (flexion) of your spine occurs whenever you sit or bend forward, so it is likely the majority of your day. Therefore it does not need to be stretched in that direction.
So try your new backwards (extension) stretch for at least 3-5 minutes, at least 1-2x/day, and you likely will get better results than other back stretches.
Ref: McKenzie, Robin. Treat Your Own Back, 9th edition. Orthopedic Physical Therapy Product: 2011.