Using the heart as a metaphor for desire, for spirit and determination against long odds, has become clichéd to the point where it's lost impact.

Only when meeting a teenager like Hunter Todd of Roseville does the phrase "This kid's got heart" actually hold true meaning.

Born with a hole in his heart as a result of a rare congenital condition called tetralogy of Fallot, Todd underwent six surgeries by age 5, including a procedure to have a valve implanted to help regulate blood flow.

Now 16 and a sophomore at Oakmont High School in Roseville, Todd lives like any other suburban teen – hanging with his friends, riding his longboard around town, strumming his guitar and raking the leaves when Dad makes him.

But get this: Todd also is an award-winning trail runner, having won the silver medal in the 2007 XTERRA trail run in the 19-and-under category. This year, he won his age group at the 49er 10-mile trail run in Auburn and the Point Mugu 11-mile trail run.

That was good enough to qualify Todd for the XTERRA trail racing world championships on Dec. 7 in Hawaii.

Yeah, this kid really does have heart, given his early medical obstacles.

According to the National Institutes of Health, tetralogy of Fallot occurs in only five of 10,000 babies. And its severity, Sutter pediatric cardiologist Dr. Gregory Janos says, spans from minimal blockage and few restrictions later in life to severe blockage that requires significant modification of activity.

Todd's case falls somewhere in the middle of the spectrum. Though his cardiologist declined to be interviewed, Todd's father, Terry, says that his son has been given clearance to exercise as long as his heart rate remains at about 145 beats per minute, approximately 75 percent of his aerobic capacity.

Terry Todd, who runs alongside Hunter at every race, admits to being torn between the typical parental concern about keeping his son safe and letting him follow his joy on the trails.

"We certainly don't push it," Terry says. "We follow the doctor's orders. Basically, our doctors have always said that it's based on how Hunter feels. Whatever he's feeling is what we do."

And what Hunter has felt like doing, since age 10, is trail running. He started out competing in shorter duathlons and runs sponsored by Total Body Fitness in Rocklin, then went off road and into nature for his first XTERRA race in 2006. It was only a three-mile race, but he won his age group.

His success caught the eye of Mark Shaw, a triathlon impresario at Total Body Fitness, which now sponsors Todd in races.

"Based on Hunter's 'quote- unquote' limitations with his heart, what he's been able to do is, in a sense, greater than a kid with supposedly no 'limitations,'" Shaw says. "I've known him for seven years, and it's great to see how he's developed."

Todd is modest about his victories – though his father has hung the medals in the hallway of the family's Roseville home.

Winning races, he says, is "pretty awesome. There are a lot of hills (in XTERRA), and you get to do crazy stuff like going over cliffs that are maybe two feet wide. There are some hard courses to put your body through."

That was only the beginning, though. For the last 20 weeks, Hunter and his father have spent every weekend on the trails for at least three hours at a time. They've become quite familiar with the American River 50 (mile) and the Western States 100 courses.

"But we take our time and don't push it," Terry says. "We walk on all the uphills. It's been a progressive and slow build."

Exercising caution is prudent, Terry says. Recently, in addition to Hunter's yearly visit with his cardiologist, he traveled to UC San Francisco Medical Center for a battery of tests, ranging from treadmill stress tests to 24-hour heart-rate monitoring. Father and son also managed to work in a long training run on Mount Tamalpais in Marin County before heading in for an MRI.

Janos, the Sutter cardiologist, says doctors have become more "liberalized" about allowing tetralogy of Fallot patients to participate in activities.

"We've gotten smarter that way over the years and seen more of these kids get older, so we can see what they can and can't do," he says. "Frankly, we were a little bit protective. And now we feel by getting kids involved and active, it helps.

"The worst thing you want in a child who's got a residual heart disease is to be overweight and out of shape. When they get to be an adult, what was one problem is now three problems."

Todd's attitude has always been: Problem? What problem?

"I wouldn't have known the difference (in my heart) if they hadn't told me," he says.

After next week's world championships, Todd says he's thinking of giving up trail running. But it has nothing to do with his heart.

"I want to try mountain biking," he says.

Call The Bee's Sam McManis, (916) 321-1145.