Prosperity fostered convenience, which encouraged inactivity—or so a doctor reportedly told the founder of Yamasa Tokei Keiki. In response, the company released the world’s first commercial pedometer, the manpo-kei. Kei means “meter,” and manpo, “10,000 steps.”
In East Asia, 10,000 had long been shorthand for plenty, or even infinite vastness, but affixed to a fitness gadget the number solidified. Once a medical researcher endorsed 10,000 steps as the threshold for being an “active” adult, manpo crossed from idiom to science and, in the process, became the best kind of goal: exact, plausible, and resettable. A wave of walking clubs overtook Japan.
Americans, wedded to their own conveniences, were slow to catch up. Sure, running took root as a pastime in the ’70s, and an ’80s fervor for “mall walking” led…
