A restraint system for may include a vehicle seat suspended above a floor of a vehicle and a restraint harness coupled to the vehicle seat and configured to restrain an occupant of the seat. The restraint harness may include at least one shoulder web configured to extend over a shoulder of an occupant of the seat and at least one lap web configured to extend over a lap of the occupant. At least one deformable member may be attached to the vehicle seat and configured to deform and dissipate energy when a force is applied thereto by the at least one shoulder web in response to an upward transient force of sufficient magnitude applied to the vehicle seat. A restraint harness pre-tensioning system may be responsive to a signal produced by a vehicle event sensor to tighten the at least one lap web about the occupant.