Abstract: An exercise ball may provide two independent sections, a first separable section and a second separable section, that a user may utilize for weight training and mind-body exercises. The first separable section and the second separable section may be held by a user in opposite hands for weight training and other exercises. The exercise ball may be a Tai Chi ball that may include a plurality of polymagnets provided in an interior of the exercise ball that may keep the two separable sections together. The plurality of polymagnets may provide a push-release or twist-release attachment and detachment to attach and detach the sections.

Abstract: An exercise ball may provide two independent sections, a first separable section and a second separable section, that a user may utilize for weight training and mind-body exercises. The first separable section and the second separable section may be held by a user in opposite hands for weight training and other exercises. The exercise ball may be a Tai Chi ball that may include a plurality of polymagnets provided in an interior of the exercise ball that may keep the two separable sections together. The plurality of polymagnets may provide a push-release or twist-release attachment and detachment to attach and detach the sections.

Abstract: In one embodiment, a wheelchair comprises an armature configured to be manipulated by a user of the wheelchair during a propulsion stroke to drive at least one wheel of the wheelchair, wherein the armature is extensible such that its length increases as it is moved away from the wheelchair user. In another embodiment, a wheelchair comprises a gear mechanism configured to drive a wheel of the wheelchair in at least one direction, the gear mechanism including an electronically-controlled actuator that is configured to control a direction in which the wheel can be driven.