US Patent 10105570 Never Tire™ exercise apparatus

A tire-like exercise device having a substantially round outer periphery and a non-round inner periphery. The non-round inner periphery may be substantially rectangular and have one or more flat regions to provide hand and toe holds for performing various exercises. A first valve allows the firmness of the Never Tire™ exercise apparatus to be adjusted by increasing or decreasing inner air pressure. A second larger valve allows ballast, such as water or sand, to be input to the device to stabilize the apparatus against slipping and sliding.