A head restraint (14) for helping to protect an occupant (60) of a vehicle seat (20) includes a base frame (150) connected to the vehicle seat. A cushion carrier (350) is supported on the base frame (150) by a track assembly (440) that facilitates movement of the cushion carrier (350) relative to the base frame (150) along a deployment axis (18) from a non-deployed condition to a deployed condition. The track assembly (440) includes a fixed track member (182) that forms a portion of the base frame (150). The fixed track member (182) includes spaced axially extending beam portions (190) with opposing surfaces (200) that define a channel (184) between the beam portions (190). The track assembly (440) also includes a sliding track member (370) that forms a portion of the cushion carrier (350). The sliding track member (370) includes a sliding frame (372) positioned in the channel (184) and having portions (442) positioned in sliding contact with portions (444) on the opposing surfaces (200) defining the channel (184).