Active head restraint
When the occupant’s lower back presses against the seatback during a rear-end collision, the head restraint moves slightly forward and upward to help reduce the risk of whiplash on the seat occupant.
Even small forces applied to the seatback may cause the head restraint to move. Pushing up a locked head restraint forcibly may make the inner structure of the head restraint appear. This does not indicate a problem.
If the seat is too reclined, during an accident the lap belt may slide past the hips and apply restraint forces directly to the abdomen or your neck may contact the shoulder belt, increasing the risk of death or serious injury.
Adjustments should not be made while driving as the seat may unexpectedly move and cause the driver to lose control of the vehicle.