Abstract: Devices, systems, and methods for supporting the body of user are described. Devices, systems, and methods can employ a plurality of cells where each of the cells within the plurality of cells can comprise a bladder containing air or another compressible fluid supported by a base that forms a fluid-tight seal with the bladder The base and bladder can be constructed and arranged so that the bladder forms a rolling diaphragm portion with the base. The height and/or applied pressure in response to an applied load of such bladder may be adjustable substantially independent of the crosssectional shape and dimensions of the bladder. Each of the cells within the plurality of cells which may be a subset or all of the cells of a given support, can also comprise, or otherwise be operatively associated with its own: pressure sensor, height sensor, or both, and/or controllable inlet/outlet valve(s).