I've had a bad back for about 12 years now. it was dignosed as slipped disk between L4 &L5. The Doctor I went to suggested back extention excercises. I have been working on my back regularly and even playing some tennis.
My problem is that my back stiffens up at night (no matter how I sleep). Waking up is a pain and any bending first up is painful and difficult. As the day progresses the pain goes away but the stiffness stays. I have to shake the stiffness off everytime I need to bend during the day. Which means that I have to bend two or three times before the back muscles are relaxed enough for me to be able to function in any bending situation. After that as long as the back muscles are warmed up I can do practically anything- including playing tennis and complex Yoga aasana. Does it look like my back muscles have lost their elasticity? Is that the reason my back takes time to "open up"? Simple things like bending to get something out of the fridge need to be done by first spending a minute or two to loosen up my back muscles.