US Patent 11628346 Adjustable hardness punching bag

A variable hardness punching bag is disclosed herein. The punching bag comprises a core having a first hardness profile; and at least one auxiliary shell attachable to the core, wherein the at least one auxiliary shell has a second hardness profile different to the first hardness profile. The auxiliary shells include a punching shell and a kicking shell, wherein the punching shell is denser and harder relative to the kicking shell. The punching and kicking shells include attachment straps for facilitating attachment to the core.