“Three times, America has seen distance-running skyrocket, and it’s always in the midst of a national crisis. The first boom came during the Great Depression, when more than 200 runners set the trend by racing 40 miles a day across the country in the Great American Footrace. Running then went dormant, only to catch fire again in the early 70s, when we were struggling to recover from Vietnam, the Cold War, race riots, a criminal president, and the murder of three beloved leaders. And the third distance boom? One year after the September 11th attacks, trail-running suddenly became the
fastest-growing outdoor sport in the country.”

(Excerpted from Born to Run)