Now I know what some of you might be thinking. You're thinking: Brad, come on. Shoes are fine. Shoes are normal. Shoes are what civilized people wear. And you're not wrong — shoes do serve real purposes in many situations. But here's what I want you to consider: for the overwhelming majority of human history, nobody wore shoes. Or if they did, those shoes were little more than a thin layer of leather or plant material — just enough to protect against sharp rocks or extreme cold, nothing more. The foot itself did all the work. Every muscle, every tendon, every tiny stabilizing structure in the foot and ankle was constantly engaged, constantly responding to the ground, constantly doing its job.

Then, somewhere along the line, we started wrapping our feet in thick, heavily cushioned, motion-controlling footwear. And while that footwear solved some problems, it created others. When your foot is cradled in a rigid structure that controls its every movement, the muscles inside it stop working as hard. Over time, they weaken. The arch loses its natural spring. The ankle becomes less stable. And without even realizing it, the effects ripple upward — through your knees, your hips, your lower back — until you've got a chain of compensations running all the way up your body, all originating from the fact that your feet forgot how to be feet.