Abstract: An active sitting chair is provided that encourages a sitter/user to sit actively by requiring balance adjustments and core engagement. The active sitting chair can be efficiently produced while being relatively sturdy and lightweight. The main body may be a monocoque shell that includes a rounded lower portion that contacts the surface the chair is on and promotes wobble of the chair when a sitter is seated on the chair. The chair may also include built-in handles for ease of lifting and a seat portion at the top of the chair that may include a cushion or similar component for increasing the stability and/or comfort of a sitter.

Abstract: A device for moving the back and core muscles while sitting includes a rocking assembly that sits atop a base assembly, and optionally a height adjustment mechanism between the rocking assembly and the base assembly. The rocking assembly includes a rocking mechanism that sits between a base plate or platform and a seat. The rocking mechanism can be, for example, a hollow or solid hemispheric- or dome-shaped rocking mechanism, an eccentric bicylinder rocking mechanism, and/or a rocking mechanism based on an arrangement of halfpipe members. The rocking mechanisms of the exercise chair allow to the seat to rock, wobble, and/or swivel with a side-to-side rocking motion, a front-to-back rocking motion, or both a side-to-side rocking motion and a front-to-back rocking motion, and are attached to base plate and seat via a fastener that includes a solid strut that passes through the rocking mechanism and includes a plurality of Belleville washers.