We checked Running USA’s 2010 State of the Sport Report and also noticed that the number of finishers in 2011 (518,000) was only 2.2 percent higher than in 2010. That’s a measly rate of growth compared to the previous two years, during which marathoning enjoyed growth rates closer to 10 percent.

While it’s true that the first marathon boom, which kicked off in 1972 after American Frank Shorter won the Olympic marathon, petered out sometime in the mid-1980s, it’s still too early to claim that current interest in the distance is waning. At least that’s what Running USA’s statistics guru (and one of the founders of Running USA), Ryan Lamppa says, and we’re inclined to believe him.

Believe it or not, the marathoning boom we’re currently witnessing is 18 years old already. Instead of starting with gold-medal fervor, however, our renewed obsession with running long can be traced to one, generally un-athletic celebrity: Oprah Winfrey. Yes, the media mogul crossed the first and only marathon finish line of her life in 1994 at the Marine Corps Marathon in a respectable 4:29:20. “Suddenly, a person couldn’t say, ‘Oh, I’m too busy to run a marathon,’” Lamppa says. “If you’re more busy than Oprah, then heaven help you.”