"Anybody who can finish this race in less than 14 hours, while they may not be physically able to compete in the Olympics, are still elite athletes," Spinnler said. "They are among the less than one-half of one percent of the people on this planet who will ever complete a race like this."
Pat O'Brien, 43, owner of Ben's Flower Shop in Hagerstown, said it's the euphoric feeling at the end of the race that drew him back for his second 50-miler.
"When you cross the finish line, you feel about as good as you can feel after a race. And it lasts a long time," O'Brien said.
"You have to experience it to understand what it's all about," Spinnler said. "Most of these people are going to go back to anonymity after the race, but they'll know what they've accomplished."
For Dave Downin of Sharpsburg, the JFK has become something of an addiction. He was hooked after the first time he finished the race in 1986.
"It's gotten in my blood, and I don't know how to shake it," said Downin, 50, a retired law enforcement officer. "Every step of my life is training for the JFK. The next one I don't do will be because I'm dead."
Joe Robeson, 62, the former principal at Boonsboro High School, is a member of the elite 500-mile club, made up of those who have completed at least 10 JFKs. He is drawn in part by the camaraderie.
"The first time you do it, one of two things will happen - either you'll never want to see it again, or you'll be hooked," he said. "To most people it's totally crazy, but the beauty of it is that it's a family. You see the same people every year."
The race itself - a grueling course which includes 12.7 miles on the rocky, damp, leaf-covered Appalachian Trail - is just a small part of the story.
Most of the runners work full time and have families, but still find the time and energy to train for countless hours, running mile after mile every week, to prepare for this one event.
"With my schedule, and with the kids, I try to run as much as I can," O'Brien said. "I've been running about 30 to 40 miles a week for the last month, but before that I was around 25 miles a week."
Paul Betker, 51, who works full time at Mack Trucks and part time at Tri-State Physical Therapy and Fitness, has put in as many as 75 miles in a week.
"You're never too old to get out and run, and stay healthy," Betker said.
For Dave Ruff, 42, who is a health club manager, training is a year-round activity.
"I run pretty much every day," said Ruff, a five-time JFK participant, "and I do deep-water running to keep a good level of fitness."
When Ed Beachley competed for the first time last year, the 39-year-old dentist had a goal in mind, but was happy just to finish the race.
"When I began the race, I thought I'd like to finish it in 10 hours," he said. "I wound up just over 10 hours, but that gives me something to shoot for the next time."
Liz Wood, a South Hagerstown High School junior and member of the Rebels' cross country team, waited until the last three miles of the race last year to establish her goal.
"Last year, I didn't really care about my time," she said. "In the last three miles I knew I had a chance to finish in under 11 hours, but I was really sore. I passed my (cross country) coach, and he said that I should be able to do it, so I pushed myself, and made it by seven seconds."
The quality of training and weather conditions play important roles in determining goals and race strategy. But whatever the conditions, just finishing remains the primary goal for many of the 650 runners.
"I had a dream once of finishing first," said Downin, "but it was only because nobody else showed up.
"I enjoy this thing so much I have nightmares about it. I dream I show up late."