Abstract: A kick boxing training bag includes a foam rubber padding (17) slipped onto a supporting structure provided with a hollow base (3) which can be filled with ballast, the supporting structure including two hollow cylindrical rubber springs (9, 13) connected by a rigid rod (11). The elastically flexible structure prevents any trauma to the athlete, provides greater realism of the training which can be much faster and rhythmic, can take even very strong blows without risking the fall of the bag and allows to easily make devices with different elastic responses according to the needs by changing the flexibility of the springs. Moreover, the base (3) is separable and stackable to facilitate the storage of a plurality of bags.