An omnidirectional rocking chair for abdominal exercise has a rectangular support base with a convex lower support surface with variable radii of curvature. The chair back supports only the user's lower back. Rocking the chair develops outward momentum in the mass of the user's upper back, arms and head. The minimum lower support surface radius of curvature is in its central portion and the center of that curvature is above the center of gravity of the seated user and chair. The peripheral portions of the lower support surface have larger radii of curvature. The corner portions of the lower support surface have maximum radii of curvature. The effect of progressive increase in support surface radius of curvature is to increase righting moment in the rocking motion where the respective larger radii portions contact the floor. This acts to decelerate outward rocking motion in the chair seat and user's lower back in opposition to the developed outward momentum in the mass of the user's upper back, arms, and head, which engages user abdominal trunk muscles.

An omnidirectional rocking chair for abdominal exercise has a rectangular support base with a convex lower support surface with variable radii of curvature. The chair back supports only the user's lower back. Rocking the chair develops outward momentum in the mass of the user's upper back, arms and head. The minimum lower support surface radius of curvature is in its central portion and the center of that curvature is above the center of gravity of the seated user and chair. The peripheral portions of the lower support surface have larger radii of curvature. The corner portions of the lower support surface have maximum radii of curvature. The effect of progressive increase in support surface radius of curvature is to increase righting moment in the rocking motion where the respective larger radii portions contact the floor. This acts to decelerate outward rocking motion in the chair seat and user's lower back in opposition to the developed outward momentum in the mass of the user's upper back, arms, and head, which engages user abdominal trunk muscles.

A spring actuated rocking mechanism can be attached to the legs of a collapsible chair to allow for the user to rock in the collapsible chair. The mechanism may be attached at the factory or retrofitted to the chair. The rocking mechanism can be attached to the end of a leg or disposed within a leg, having a leg portion above and below the mechanism.

A spring actuated rocking mechanism can be attached to the legs of a collapsible chair to allow for the user to rock in the collapsible chair. The mechanism may be attached at the factory or retrofitted to the chair. The rocking mechanism can be attached to the end of a leg or disposed within a leg, having a leg portion above and below the mechanism.

A fitness device is provided, the fitness device comprising: a spheroidal member having an interior cavity, the spheroidal member comprising a cylindrical portion extending between a first hemispherical endcap and a second hemispherical endcap, wherein a surface of the spheroidal member defines an aperture positioned between the interior cavity and an exterior of the spheroidal member; and a structured surface positioned on the surface of the spheroidal member over the aperture, the structured surface extending into the interior cavity of the spheroidal member.

A fitness device is provided, the fitness device comprising: a spheroidal member having an interior cavity, the spheroidal member comprising a cylindrical portion extending between a first hemispherical endcap and a second hemispherical endcap, wherein a surface of the spheroidal member defines an aperture positioned between the interior cavity and an exterior of the spheroidal member; and a structured surface positioned on the surface of the spheroidal member over the aperture, the structured surface extending into the interior cavity of the spheroidal member.

An active seat includes a seat disposed at a first end of a body; a convex surface disposed at a second end of the body; and a stacking notch defined at an intermediate location along the body. The convex surface defines at least a first rocking path about which the active seat tilts. The stacking notch defines a flat surface recessed laterally inwardly from an outer periphery of the body taken at the first and second ends.

An active seat includes a seat disposed at a first end of a body; a convex surface disposed at a second end of the body; and a stacking notch defined at an intermediate location along the body. The convex surface defines at least a first rocking path about which the active seat tilts. The stacking notch defines a flat surface recessed laterally inwardly from an outer periphery of the body taken at the first and second ends.

A stool and desk support system. The system includes a stool base and a desk support surface. A support member may connect the desk support surface to the stool base and support the desk support surface above a floor surface. The stool base may include a stool seat surface and a rocking mechanism opposite the stool seat surface. The desk support surface may be connected to a desk support base by a neck extending from the desk support base. The stool base may include an upper stool base frame and a lower stool base frame. The upper stool base frame may be height adjustable with respect to the lower stool base frame. The desk support base may connect to the upper stool base frame, permitting coinciding height adjustment of the desk support surface and the upper stool base frame.

Furniture pieces are disclosed. A furniture piece includes a body, a non-flat base surface, a seat surface, a back protrusion, a pair of opposed side surfaces, and apertures. The non-flat base surface is positioned on a first side of the body, and the seat surface is positioned on a second side of the body opposite the first side. The back protrusion extends outward from the second side of the body adjacent the seat surface. The pair of opposed side surfaces are positioned on opposite sides of the body extending between the first and second sides. Apertures are defined in each of the side surfaces. Each aperture has an upper surface facing in a direction opposite the seat surface.