An energy absorbing extruded bumper for a vehicle is formed from a lightweight metal, preferably aluminum base alloy material. The extruded bumper includes an outer wall, an inner wall, a top wall connecting the outer and inner walls, and a bottom wall connecting the outer and inner walls. Extending between the outer and inner walls are two or more s-curved trigger stiffeners. The trigger stiffeners include an upper s-curved trigger stiffener connecting the outer and inner walls and a lower s-curved trigger stiffener connecting the outer and inner walls. The lower s-curved trigger stiffener is spaced apart from the upper s-curved trigger stiffener.