1. A prosthesis device comprising: a residual limb model comprising a residual limb portion having elastically deformable properties, a substantially hollow internal core forming a cavity, and configured to resemble a residual limb; and a bladder having a closed, elongated cylindrical body that is complementary in shape to the residual limb portion; wherein the bladder is removably insertable within the cavity of the residual limb portion such that the bladder substantially fills the cavity of the residual limb model to form a structure configured to be inserted into a check socket to facilitate training in donning and doffing of a prosthesis and training in care of the residual limb, and the bladder being configured such that inserting the elongated cylindrical body into the cavity substantially fills an entire volume of the cavity to form a substantially filled cavity such that inflation of the bladder outwardly expands an elastic outer layer of the residual limb portion, and deflation of the bladder inwardly contracts the elastic outer layer of the residual limb portion to simulate at least one of a volume change in the residual limb, edema in the residual limb, and shrinkage in the residual limb; wherein the simulated volume change in the residual limb portion trains an amputee to manage and control limb volume changes within the residual limb; wherein the simulated edema in the residual limb portion trains the amputee to care for an edematous limb; and wherein the simulated shrinkage in the residual limb portion trains the amputee to shrink the residual limb and perform skin care in preparation for the prosthesis; and wherein the check socket is configured to retain at least a portion of the structure of the residual limb model such that the residual limb model is complementary in shape to the check socket.