Abstract: An apparatus (10) for helping to protect the lower extremities (44) of an occupant (40) of a vehicle (12) includes a sheet member (50) for extending along the floor (14) of the vehicle. The sheet member (50) has a surface (58) extending under the occupant's lower extremities between opposite first and second end portions (54, 52) of the sheet member. The sheet member (50) has a first condition in which the sheet member is spaced from the vehicle floor (14) by a first distance. The apparatus (10) includes an actuatable power source (84) for pulling at least the first end portion (54) of the sheet member (50) to tension the sheet member between the first end portion and the second end portion (52). The apparatus (10) also includes a vehicle crash sensor (80) for actuating the power source (84) in the event of a vehicle collision to tension the sheet member (50) and move the sheet member from the first condition to a second condition.