LONDON (Army News Service, Aug. 11, 2012) -- Staff Sgt. John Nunn finished 43rd in the Olympic 50-kilometer race walk Saturday with a personal-best time of 4 hours, 3 minutes, 28 seconds.

Nunn, 34, a two-time Olympian in the U.S. Army World Class Athlete Program, or WCAP, progressively worked his way forward in the field of 63 competitors after passing the five-kilometer mark in 59th place. While other fatigued walkers dropped from the race, Nunn surged back and gained nine positions during the final 10 kilometers.

"There were guys dropping right and left around me," said Nunn, 34, a native of Evansville, Ind., who is stationed at Chula Vista, Calif. "So I thought, well, this is good, we can keep [passing] some people."

Russia's Sergey Kirdyapkin eclipsed the Olympic 50k record by more than a minute and won the gold medal with a time of 3:35:59. Australia's Jarred Talent took the silver in 3:36:53. China's Tianfeng Si claimed the bronze in 3:37:16.

Race walking was one of the few Olympic events that could be attended without an expensive ticket and thousands of spectators lined the course. Bleachers at the start/finish line required a ticket, but a throng of fans swarmed the Mall in St. James Park.

The course was a two-kilometer loop that began near the Marlborough House, passed the front gate of Buckingham Palace, and went up the slight grade of Constitution Hill before turning back toward Admiralty Arch.

The 25-lap course began taking its toll on several of the race walkers about two-thirds of the way through the race, which covered just over 31 miles.

"I don't know when it is, probably about 30 or 35k, your vision starts to go," Nunn said. "At least for me, the outer area starts to get blurry and you just get tunnel vision."

Nunn said he forced himself to just keep putting one foot in front of the other as his mind played tricks on him. The sounds of the crowd faded away and he focused on the race, taking it one kilometer at a time.

Eight walkers were disqualified from the race and four others did not finish the event contested in hot and sunny conditions.

"The 50k is absolutely the most grueling track and field event there is," Nunn said.

Nunn has been training for the 50k for less than nine months. He has been race walking for almost 20 years, but until this past year, has always competed in the 20k. He competed at the 2004 Olympics, finishing 26th in the 20k race walk in Athens, Greece. He failed, however, to qualify for the 2008 Olympics.

This time around, he decided to try the 50k. Nunn compared himself to veteran 5k and 10k runners who have moved up to compete in marathons.

"Eventually you reach a point where you just don't have the speed to stay with the quick guys, and you move up to the marathon because you can get the distance and the speed," he said.

Nunn won the 50k Olympic Trial with a time of 4:04:41. He went on to compete in the 20k event at the U.S. Olympic Track and Field Trials in Eugene, Ore., where he dropped out because of a nagging hamstring.

In the middle of the Olympic 50k race in London, Nunn said his right hamstring began to bother him when he applied a sponge to his leg.

"I was taking sponges, and when the water hit the back of my right leg, the leg cramped, eventually the water got off and the muscle relaxed."

His hamstring was pain free for the remainder of the race, until the last lap, when he said it began to cramp again.

"I'm glad it was only 50k and not 52, because it would have been a hard push the last lap," Nunn said.

Nunn said the aftereffects of the race would linger well into the night.

"I won't go to sleep tonight probably until 2 or 3 because the neurons and everything, the muscles just keep twitching involuntarily," he said. "So you can lay back and just watch your legs, and they keep firing everywhere. It's so frustrating because you're trying to relax, and your body just won't."

Nunn said many Americans poke fun at race walking and don't realize the sport's level of difficulty. He said if they just tried it, they would sing a different tune.

"I mean, it is an absolutely grueling event," he said. "It is very, very hard to get the feel for it, to understand, and your body is in a lot of pain."

To prove the point in London, on two different occasions, Nunn invited NBC correspondents to try to race walk. The network aired a piece Friday night in which Nunn attempted to teach an announcer how to race walk.

"He was trying to do it and he was having a hard time," Nunn said, adding that he was just glad the NBC guys gave it a try.

On an NBC Today Show segment that aired July 30, six co-hosts of the program tried to learn race walking.

Nunn and his Olympic teammate, Maria Michta, spent a couple of hours teaching Al Roker, Matt Lauer and Ryan Seacrest how to race walk, along with Savannah Guthrie, Natalie Morales and Meredith Vieira.

"I find this very difficult," co-host Lauer said.

NBC producers said they selected race walking as a sport to showcase because they thought it would be fun, interesting and unfamiliar to most Americans.

In race walking, one foot must remain in contact with the ground at all times. The second rule is the front leg must remain straight when it touches the ground and stay that way until the body passes over it.

Nunn and Michta huddled with the Today Show staff and explained the rules. After some demonstration, they had the co-hosts try it.

"On your right, your arms kind of flail a little bit," Nunn said to Ryan Seacrest. "You can bring it in."

Then the NBC talent joined Nunn for a partial lap around the track.

"We went about 90 yards, that's it," Nunn told the group. "Look how hard you're breathing.

"Not to make you feel bad, but that was our warm-up pace," he said.

At the end of the Today Show segment, the six stars raced each other in a competition, ultimately won by Roker, and some of the broadcasters gave up and stopped. Nunn awarded Roker a golden sneaker for finishing first.

A couple days later, Ryan Seacrest reportedly complained his shins "were on fire" after attempting the race walk.

Nunn said race walking involves muscles that are not used very often by most people, including other athletes. But he plans to continue the sport as long as he can.

He will take a year off from the Army World Class Athlete Program and go back to school, but said he would then like to come back and resume training for the world championships and the 2016 Summer Olympics in Rio de Janeiro, Brazil.

He has the support of his mother and 8-year-old daughter, Ella. They joined him in London to watch the race walk.

"Hopefully I can make 2016," Nunn said.