Gymnastic ball used as seat

摘要

The gymnastic ball has its seat face covered by a cushion (2) and has on the opposite side a counterweight (3) of at least the weight of the seat cushion. Pref. the seat cushion is dish-shaped, as is the counterweight. The seat cushion and counterweight may be interconnected by belts (4).The belts are formed by a continuous length of belt passed through eyelets (5) in the seat cushion and the counter-weight in an intersecting manner. The seat cushion may be held in position by a net, or an adhesive, the counterweight being glued in position.