Abstract: Disclosed is a back supporting device for use with seating apparatuses. The back support device includes a bag containing at least one compartment holding a predetermined amount of fluid, liquid or gel, a flexible cover encasing the bag, and fastening elements for securing the device to the seating apparatus. The device is secured to a seating apparatus to secure the device in place. The fluid, liquid or gel inside the compartment is able to move in response to an application of pressure. When seated, the person's back presses against the device, in particular, the fluid, liquid or gel in the bag, causing the substance inside the bag to move in multiple directions in response to the movement of the person, thereby providing support and at the same time inducing muscle movement and reducing muscle fatigue in the back of the person, in particular in the lumbar region.