Abstract: An exercise device includes an inflatable bladder and is partially stabilized with a small amount of filler. The bladder includes a first aperture to allow the filler to be easily placed in the bladder. The bladder also includes a valve main body that allows air to be easily injected into the bladder to inflate the bladder. In an exemplary method the filler is forced into the inflatable bladder using a mixture of air and filler. The air is under pressure and assists in forcing the filler into the bladder. After a proper amount of filler is in the bladder, the bladder can be deflated for packaging and/or shipping.

Abstract: A stability ball is disclosed that includes an inflatable bladder with a filler such as sand disposed therein. The amount of sand is selected to stabilize the stability ball with respect to a support surface, thereby preventing the stability ball from moving on a flat surface when the stability ball is not being utilized by the user. The amount of filler is sufficiently small that the user is substantially unaffected by the extra weight when performing core body exercises.