UPON ENTERING MY VEHICLE, SITTING IN THE DRIVER'S SEAT, AND RESTINNG MY BACK AGAINST THE SEAT WHILE IN AN UPRIGHT POSITION, THE BACK OF THE SEAT COLLAPSED.THIS ALL OCCURRED PRIOR TO THE VEHICLE BEING STARTED AND ENGAGED IN ANY GEAR, WHICH IS PROBABLY THE ONLY REASON THE INCIDENT DID NOT RESULT IN A SERIOUS OR FATAL ACCIDENT. DUE TO THE COLLAPSE OF THE SEAT, I DID SUSTAIN A BACK INJURY/STRAIN.