Cindy Ann Peterson said this quote

Posture and Social Status...During the 18th century in European and American society, aspects including station in life, status and dress could easily identify those of financial means. In fact, the garments of this era would hold the wearer in a position that would support and require proper posture. Women, and sometimes men, wore stays in order to shape the torso. Among the more privileged, even children wore stays since people believed these improved their posture and enhanced straight spinal growth. Certain movements were constrained by the cut and design of many garments, including details of the sleeve and back that would hold the person in proper posture.