Abstract: Optical fiber core including a plastic buffer tube loosely containing individual optical fibers or a plurality of coplanar fibers in a plastic ribbon, which fibers and ribbon are longer than the buffer tube, at least two flexible strength members of a tensile strength greater than the tensile strength of the tube and having a coefficient of expansion and contraction less than that of the tube, at the outer surface of the tube and an adhesive binding the strength members to the tube and/or a tape or cord under tension around the strength members to prevent slippage of the strength members with respect to the tube and to prevent buckling of the strength members when the core is subject to compressive forces. Also, an optical fiber cable containing such core.