Abstract: Reinforcement elements intended for use in door leaves of the kind consisting of fabric or similar flexible material. The reinforcement elements preferably are in the shape of tubes and have end pieces attached to their ends for cooperation with a profiled guiding member mounted in the door-frame of the door leaf in such a manner that when the door is being closed said reinforcement elements will be positioned at different predetermined levels of the door leaf, thus strengthening the latter to prevent bulging of the door leaf when the latter is exposed to heavy winds.