The invention relates to a strut, such as fiber composite struts used in aircraft or spacecraft, which has a largest possible outer diameter within a cylindrical installation space of the strut. The invention concerns an insert connected to a fiber composite hollow structure, such as a fiber plastic composite hollow structure, where the hollow structure engages an undercut of the insert, wherein the outer region of the fiber composite hollow structure likewise has an undercut and this undercut is filled with a fiber composite jacket, such as a fiber plastic composite jacket, and the inner region of the fiber composite hollow structure has, at least in one subregion, a core connected thereto.