The first thing I warned Mandy Lieveld about was that I slouch like a female version of Bernie Sanders. “Ik zei tegen haar: ‘Als ik op hakken loop, is het alsof ik buig onder de zwaartekracht.'” Lieveld, a former model who trains others to navigate the challenging “runways” of fashion shows, appeared unfazed. Her role involves instructing models—and non-models—on how to walk the runway confidently. She’s a bit of a high-fashion gait expert, turning clumsy fawn-like steps into commanding marches for brands like Michael Kors, Versace, and Bottega Veneta. I discovered Lieveld, 40, via author Zoe Dubno, who was selected to walk in Rachel Scott’s debut Proenza Schouler show in February. Though flattered, Dubno felt a rising panic. “I have sort of a Groucho Marx walk,” Dubno said. Worst of all, she would have to walk in heels—which she regarded as dizzying torture instruments, otherwise reserved for hobbling around her brother’s wedding. The Proenza Schouler casting team hired Lieveld, and after two days of coaching, she turned Dubno’s gait from a comedian’s clomp to a supermodel’s stroll. I was intrigued. Would the Lieveld treatment benefit me? Could she correct my (undiagnosed but long suspected) scoliosis and fix my slouching trudge to Key Food?