Best stretch for back??

Joan G.
The best one I find is the cat-cow stretch. So your on your hands and knees you arch your back upwards like a scared cat, hold for a few seconds. Then you arch your back downwards and look up with your head pushing your abs towards the ground.
Priska W.
Back twist.

Lay flat on your back,
Lift you knees to a 90 degree angle
Left them fall to the right with the top left slight outstretched
Arms straight out to the side
Turn your head to the left trying to keep both shoulders on the floor.

Repeat the other side
Its a great twist!