An automotive seat assembly with improved side impact rigidity is provided including a seat frame. The seat frame includes a frame track, a frame base slidably engaged to the frame track, and a frame back rotatably engaged to the frame base. A rear lateral support assembly includes a support frame attached to a rear portion of the frame base such that the support frame is movable in concert with the frame base. The support frame defines a pocket portion. A tubular member is positioned within the pocket portion. A rocker panel end cap assembly secures a first end of the tubular member within the pocket portion. The rocker panel end cap positioned to engage a rocker panel during side impact. A tunnel console end cap assembly secures a second end of the tubular member within the pocket portion. The tunnel console end cap assembly is positioned to engage a tunnel console such that the tubular member generates a rigid support between the rocker panel and the tunnel console.