The present invention provides a method for producing a bending-resistant, elongated body, preferably a shaft or beam. The invention is characterized in that an elongated blank is produced having at least one cavity extending essentially along the entire length of the blank, the inner surface of which cavity is at a distance from the mass center of the blank seen in a section at right angles to its longitudinal axis and that affixed in the cavity is a fiber composite body with an outer surface essentially congruent with the inner surface of the cavity and that majority of the fibers in the fiber composite body both extend essentially parallel to the longitudinal axis of the elongated blank and are elongated along the whole of its length. The invention also relates to an arrangement produced according to the method.