A structural body of a vehicle comprises: a hollow component comprising walls that define a channel, wherein the component has a component length, and wherein the component is selected from the group consisting of beam, rail (58), pillar (50,52,54,5), chassis, floor rocker (60), and cross-bar, or combinations comprising at least one of the foregoing; and a plastic-metal hybrid reinforcement (1) having cavities therethrough (14), and a support (6) having greater than or equal to 3 walls forming a support channel. The plastic element (4) is located in the support channel (6) wherein the reinforcement (1) is located in the component channel.