Abstract: A dynamic support system mounted to a chair to permit a user to be supported in one of a plurality of positions is provided. The dynamic support system includes a seat assembly coupled to the chair and having a cushion and a pair of support plate assemblies coupled to the cushion, each support plate assembly having a central interface plate coupled to the chair and disposed between an inner interface plate and an outer interface plate, the central interface plate of each support plate assembly having a pair of pivot slots, the inner and outer interface plates of each support plate assembly coupled to the cushion by a pair of bolts extending through the inner interface plate, the pair of pivot slots in the central interface plate and the outer interface plate of each support plate assembly. The seat assembly can adjust between an anterior position and a posterior position.