A vehicle seat assembly is provided with a seat back frame with an upper crossbar. A deformable member is welded to the seat back frame. A pair of tubes is welded to the deformable member. A pair of head restraint posts are each received in one of the pair of tubes to support a head restraint. A pair of spaced apart limit bracket bases is welded to the upper crossbar and extend away from the seat back frame to support a pair of limit bracket contact portions. A pair of contact target plates are each welded to one of the pair of tubes, spaced apart from and aligned with one of the pair of limit bracket contact portions so that the deformable member deforms under a rear vehicle impact until the contact target plates contact the contact portions of the limit brackets.