The velcro snags on my mesh jersey with a sound like a small, angry animal being unzipped, a sharp, static friction that punctuates the silence of the 5:03 AM air. I am sitting on the edge of the bed, the pre-dawn light filtering through the blinds in thin, gray slats, trying to ignore the way my left calf feels like it has been replaced by a tightly wound violin string. I pull the sock over my heel, a deliberate, slow movement. My Garmin chirps from the nightstand. It’s a 73-dollar piece of silicone and circuitry that thinks it knows me better than I know myself. It tells me my recovery is complete. It tells me my sleep score was an 83. It is, for all intents and purposes, a very expensive, very sophisticated liar.

I ignore the twinge. I always ignore the twinge. This is the 13th time this year I have felt this specific heat in my lower leg, a dull throb that radiates from the medial edge of the tibia. I tell myself it’s just the cold. I tell myself that because I spent 253 dollars on carbon-plated shoes, the physics of the foam should somehow override the failure of the bone. I lace them up-tensioning the strings until the bridge of my foot feels 43 percent more stable-and stand up. The pain