A height adjustment apparatus for a workstation, work table (200, 210, 220, 230, 240, 250, 260), shelf system, rack system and the like comprising a work platform (102, 104, 106, 128) or a shelf and a plurality of vertical support members, the height adjustment apparatus comprising: a sleeve member extending vertically along a longitudinal axis and disposed over an upper end portion of one of the plurality of vertical support members, characterized in that the sleeve member comprises a wall including a plurality of generally horizontally-oriented and vertically-spaced slots, each of the plurality of slots being defined by an upper surface and a lower surface, wherein the upper surface and the lower surface are spaced apart by a first distance; an insert attached to the upper end portion of the one vertical support member, the sleeve member being disposed over the insert such that at least a portion of the insert is located intermediate the sleeve member and the one vertical support member, the sleeve member being attached to the insert; a housing disposed over at least a portion of the sleeve member, an end cap adapter located at an upper end of the housing and coupled to the work platform or shelf, wherein the housing is moveable along the sleeve member and the end cap adapter and the work platform or shelf are moveable with the housing; a position release having a deactivated state and an activated state and comprising a pawl pivotally coupled to the housing at a pivot location and a biasing member biasing the pawl in a first pivot direction about the pivot location, the pawl comprising a user actuation interface on a first side of the pivot location and a locking tab on a second side of the pivot location, the locking tab comprising an upper side and a lower side, wherein the upper side and the lower side are spaced apart by a second distance that is less than the first distance; wherein, when the user actuation interface is disengaged the position release is in the deactivated state and the locking tab of the pawl is operable to engage any of the plurality of slots in the sleeve member; wherein, when the user actuation interface is engaged to overcome the bias of the biasing member and to pivot the pawl in a second pivot direction the position release is in the activated state and the locking tab of the pawl is inoperable to engage any of the plurality of slots in the sleeve member; wherein, when the position release is in the deactivated state, the housing is movable along the longitudinal axis only in a first direction; and wherein, when the position release is in the activated state, the housing is movable along the longitudinal axis in both the first direction and in a second direction opposite the first direction. a sleeve member extending vertically along a longitudinal axis and disposed over an upper end portion of one of the plurality of vertical support members, characterized in that the sleeve member comprises a wall including a plurality of generally horizontally-oriented and vertically-spaced slots, each of the plurality of slots being defined by an upper surface and a lower surface, wherein the upper surface and the lower surface are spaced apart by a first distance; an insert attached to the upper end portion of the one vertical support member, the sleeve member being disposed over the insert such that at least a portion of the insert is located intermediate the sleeve member and the one vertical support member, the sleeve member being attached to the insert; a housing disposed over at least a portion of the sleeve member, an end cap adapter located at an upper end of the housing and coupled to the work platform or shelf, wherein the housing is moveable along the sleeve member and the end cap adapter and the work platform or shelf are moveable with the housing; a position release having a deactivated state and an activated state and comprising a pawl pivotally coupled to the housing at a pivot location and a biasing member biasing the pawl in a first pivot direction about the pivot location, the pawl comprising a user actuation interface on a first side of the pivot location and a locking tab on a second side of the pivot location, the locking tab comprising an upper side and a lower side, wherein the upper side and the lower side are spaced apart by a second distance that is less than the first distance; wherein, when the user actuation interface is disengaged the position release is in the deactivated state and the locking tab of the pawl is operable to engage any of the plurality of slots in the sleeve member; wherein, when the user actuation interface is engaged to overcome the bias of the biasing member and to pivot the pawl in a second pivot direction the position release is in the activated state and the locking tab of the pawl is inoperable to engage any of the plurality of slots in the sleeve member; wherein, when the position release is in the deactivated state, the housing is movable along the longitudinal axis only in a first direction; and wherein, when the position release is in the activated state, the housing is movable along the longitudinal axis in both the first direction and in a second direction opposite the first direction.