The present invention relates to a device wherein an elastic body which is shaped to conform to the curvature of the back of a human body (spine), and which is repulsive against bending and tensioning, is worn on the torso by upper/lower wearing belts； bending force occurring due to the weight of the upper part of the human body during a bending/stretching exercise is stored as repulsive force of the elastic body； and the repulsive force is reused when the human body is stretched, thereby reducing consumption of force required for bending/stretching. The present invention is characterized in that a composite elastic body or a leaf spring is designed in a block type such that bending repulsive force from the leaf spring and tension of a separate coil spring are combined, making it possible to adjust the total bending repulsive force； the composite elastic body or leaf spring is shaped like a coil such that the resulting integrated elastic body has bending/tensioning/rotating repulsive force； the integrated elastic body can respond to bending, tensioning, and twisting resulting from a physical exercise； and the action of the elastic body can be improved/enhanced by external force. The present invention relates to a bending/stretching capability improving device worn on a human body, which reduces a load on the waist in an equivalent amount to the combination of an acting repulsive force from an elastic body and an action of a tension winch during a bending/stretching exercise or when a weight is lifted, and which accordingly reduces damage to the waist.La présente invention concerne un dispositif au moyen duquel un corps élastique dont la forme est adaptée à la courbure du dos d'un corps humain (colonne vertébrale), et qui exerce une répulsion à la flexion et à la tension, est porté sur le torse par des ceintures de port supérieure/inférieure； la force de flexion se produisant en raison du poids de la partie supérieure du corps humain pendant un exercice de flexion/d'
