At the trend's mid-1980s peak, close to 4,500 Parcourses studded the land, along with hundreds of knockoffs sold by rival firms. There were Aqua Parcourses for swimming-pool sessions, "joint-use" Parcourses for disabled people, indoor Parcourses, cruise-ship Parcourses, and dozens of corporate-sponsored employee Parcourses, not only in the United States but in more than 25 countries the world over. These days, many have gone the way of Hacky Sacks and A Flock of Seagulls. "The courses are relics now," says a wistful Richard Cunningham, former owner of equipment-maker Parcourse Ltd. "But there was a time when you could stand on a corner in Silicon Valley, in Santa Clara, and see four different Parcourse facilities. It was a boom time. There were probably a hundred of them in San Jose. I bet you'd have a hard time finding a dozen of them now."

Still, rumors of the courses' extinction have been greatly exaggerated. An Alabama playground-equipment maker called GameTime continues to sell new, tubular steel course equipment at a rate of 30 sets per year. Boyd Sign Company in Beaverton, Oregon, even sells replacement signs for dilapidated circuits. And Parcourses of varying ages endure from Juneau to Sedona to Disney World to Negril—all waiting for a 21st-century revival that may be less far-fetched than it sounds. "There is a trend now in fitness clubs," says Judy Hobbisiefken of the International Sports Sciences Association, an organization that certifies personal trainers. "Some places call it core training, others call it basic training, where they set up stations in an aerobics room and do the exact same exercises. Parcourses basically take that idea and say, 'Look, it's way more fun to do it outside.'"