A composite structural article (100) includes a polymeric body (35) having a first major surface (24) and an opposing second major surface (22) and a rib element (30) extending away from the first major surface. A reinforcing member (10) is embedded within a free end portion (34) of the rib member (30). The reinforcing member includes an elongated polymer rod having a rod length and a plurality of co-extending continuous fibers (20), embedded and distributed within the elongated polymer rod. The fibers are under tension and may have a helical or twisted configuration along the rod length.