Bernie Kukar will never forget his first Super Bowl. He walked out onto the field in Miami, his heart pounding, his palms sweating. The cheers subsided as he stood in the center of the field and the National Anthem began to play.
"Boy oh boy," he thought. "I better not screw up this coin toss."
After 15 seasons of officiating in the National Football League, Kukar had finally arrived. He was head referee at the country's premier sporting event.
During a career that's spanned nearly five decades, Kukar's heard his share of referee jokes and more than his share of criticism from outraged pro football fans.
"If you had one more good eye you'd be a cyclops," and, "Hey ref, you're missing a good game," are both crowd favorites.
While it's easy for football fans to criticize the men in stripes who make the calls, not many couch potatoes with beer bellies can run six miles -- the average distance an NFL referee runs in a three-hour game.
The physical and emotional demands of officiating in the NFL means the referees must be athletes in their own right. Professors Jon and Kathleen Poole have worked with the select group of 120 men who officiate games across the league each summer.
The Pooles, husband and wife, both teach in the department of exercise, sport and health education at Radford University, and have worked with NFL officials to develop a physical fitness and nutritional program over the past 11 seasons.
The Pooles and their team of researchers conducted a 10-game study of the physical demands on a referee during an NFL game.
What they found was surprising to even the 58 officials who wore monitors as part of the study. Kukar was one of them.
"As far as I could tell, we were probably running two to three miles per game," said Kukhar. "I was kinda surprised when they told me it was more like six miles. I didn't think we were running that far."
At an average age of 51, NFL referees are in top shape for their age group. They stay in their maximum heart rate zone for 73 percent of a game, burning a whopping 709 calories and shedding more than two pounds per contest.
The findings shed light on an occupation many Super Bowl fans know little about and often underestimate.
"Public perception is that we're a bunch of old guys who can't move and can't run and just happened to be in the right place at the right time to get this job," said Kukar.
Jon Poole echoed that sentiment.
"We see cartoons that have an overweight guy wearing a referee shirt, but the reality is these guys are very high-level officials," he said. "The vast majority are very, very fit."
Now retired, Kukar said he never took the insults personally.
"You gotta have a thick skin in this business," he said. "We don't pay attention to it. In the locker room after the game, we wonder who won the 'boo' contest."
Officiating is a job that's difficult to compare to other occupations. Refs need a wealth of knowledge like a lawyer, but must also be in peak physical condition to keep up with the 25- and 30-year-olds they run down the field with.