a vehicle system for aiding in the protection of a vehicle occupant is disclosed . the system includes a seat assembly having a seat base and a seat back and a pelvic bolster rotatably attached to the seat back of the seat assembly . the pelvic bolster is rotatably movable between a first stowed position and a second deployed position . a reversible motor drives the pelvic bolster between its stowed position and its deployed position . the system further includes a threat condition sensor operatively associated with the reversible motor .