Disclosed herein are methods for producing core-sheath structures by shaping at least one filament bundle containing a plurality of filaments to form at least one shaped strand of filaments, and braiding a plurality of strands, including the at least one shaped strand of filaments, over a core to form the core-sheath structure containing a braided sheath of the strands surrounding the core, wherein the shaped strand of filaments is an untwisted strand having a twist level of less than 1 turn per meter, a cross-sectional aspect ratio of the shaped strand of filaments is at least 3:1, as measured in the braided sheath, a thickness of at least a portion of the braided sheath ranges from about 10 to about 200 μm, and the braided sheath comprises a synthetic fiber having a tensile strength of greater than 12 cN/dtex. Also disclosed herein are core-sheath structures formed by such methods.