The first time my hips locked up, the reason was at least a little bit glamorous. It was 2018, and I was returning from vacation in Sicily, which was the fanciest thing I’d ever done by several orders of magnitude. As I went through the motions—and, perhaps more important, the lack of motion—of international flight, my gait began to stiffen, and my stride contracted to a fraction of its former self. My body, settling into its mid-30s, rebelled against the hours spent in airplane seats, the nights in unfamiliar beds, the constant, awkward physicality of travel.