HARD-CORE RUNNERS’ response to all the bad news? See you at the finish line.

Runners are a peculiar breed. I should know, because I was one. Training for a marathon involves getting up early, running until late, and lacing up the sneaks six out of seven days each week — for months on end. Running becomes your life, your social center, your number-one priority. Kerry Roche, 25, can tell you that. The Quincy resident is training with five girlfriends to run the Boston Marathon — their first. "We’re boring people," she tells me. "It’s all we talk about."

Bob Fitzgerald, the editor of New England Runner magazine, says that people train for marathons for one of three reasons: it’s what their peer group is doing, they’re trying to lose weight, or they’re looking to lead a healthier lifestyle.

For me, call it boredom. I started training for a marathon in the summer of 2000 for lack of anything better to do. I’d just moved to Boston, knew very few people, and even less about the city. So I ran. And ran and ran. With nothing better to do in the evenings, on weekends, whenever — I ran. I quickly became one of those runners who scoffs at the Walkman, who runs deftly with water bottles and Gatorade in tow, who knows the perfect spot in a sneaker to hide a key.

I soon found a community of runners. We’d jog in place for a few, talk about how much distance we were doing, what injuries we were nursing that day, and how much more we had to go.

Most of my new ragtag running mates were training for something. In hard-core running circles, there is, unsurprisingly, a densely layered status system. The DC marathon (Marine Corps) is considered wimpy. The Providence one (Ocean State), which I was training for, is good for first-timers, i.e., pretty wimpy. New York is above those. And as for the Boston — well, wooo-ey — that’s for the hard-core.

Injuries were par for the course. I had mine mid-training, when I took a bad fall one night, tripping over a coat hanger in the middle of Comm Ave, and skidding down the asphalt. I dug the rocks out of my knee in time to meet my friend Patrick, who was training for the DC marathon — and the next week I was running again. Call it Marathon Madness. Marathon Macho. Whatever; I just wanted to get back out there. I was losing time on my finely calibrated training schedule.

While at work one day, I did some Web searches to see how much good I was doing myself, as I absentmindedly squeezed my newly bulging quads. I came across some studies that didn’t quite fall in line with what I was expecting. There was talk of permanent bone damage, ills caused by dehydration, bad, bad things.

What? How could this be? Running was healthy! It had even compelled me to stop smoking, after years of deceiving myself that I merely enjoyed the Occasional Social Cigarette.

I defiantly shrugged off the bad tidings. I was so close to my marathon date, and I wasn’t going to stop for anything, especially something as vague and amorphous as bone damage. I mean, come on, that doesn’t happen to regularly exercising twentysomethings. Please. The only thing that was going to stop me at this point was a real, blood-oozing, painful injury. Not some potential future event.

Besides, by this point, my parents were flying out from San Francisco to cheer me on — my dad, especially, gushing with pride in his athletically inclined daughter. Like reading Ulysses or putting on an ambitious dinner party, running this marathon had become a personal test, a marker of how well I’d adjusted to my new city. Running unscathed would prove even more to myself. And somehow, despite clocking 40 miles a week at my peak, I miraculously got through training with all my limbs, muscles, and ligaments intact — although I’d lost my training buddy to a knee injury.

The race itself was something of a blur. Hopping up and down before the start, I remember being nervous about getting a bad stomachache, which induced a bad stomachache. I was concerned about things like warmth, food, hydration, peeing. I was not thinking about things like bone damage, seizure, cardiac arrest.

Pumped up, we launched to the tune of "Who Let the Dogs Out." Here’s how it went: I ran. And that’s pretty much all I remember. At a few points, I remember seeing my parents pass off peanut-butter sandwiches as I tossed them my long-sleeve shirt. I chatted with people running next to me. I mainly focused on putting one foot in front of another. Making it the next few miles — to a water station. Finding a building to dive behind for a quick pee.

I crossed the finish line in Providence, numb in the limbs, my head weighing me down, sucking madly on candy a fellow runner dug out of his shorts, and crying. I wasn’t sad. It was just the only physical response I had left. There had been laughter, there had been lots of groaning, and there had been, yes, some singing to myself.

Finishing the race felt like what I imagine giving birth to be — incredibly painful, but somehow compelling enough to repeat. You want to drop, and then (hello, endorphins; what pain?) — you want to do it all again. The pain was vaguely gratifying, even. My medal. "So, what’s next ... Boston?" asked a friend over a post-marathon pub lunch in Providence. "Hell, yeah!" I enthused, mentally planning my new regimen.

I haven’t run more than a handful of miles since: now, my left knee starts screaming by Mile Two. Sadly, my marathon madness ended at that finish line in Providence. If that hadn’t happened, there’s a good chance I would be out there on Monday too.

CALL IT ADDICTION — many do. "It’s pretty safe to say that I’m addicted to running," says Allison Lombardi, 24, who’s flying in from California to run the Boston Marathon. "If I don’t run one day or a couple days in a row, I get pretty antsy, and I feel pretty yucky."

Lombardi has had shin splints for eight years. Over the course of her running career, which has included running track and cross-country on athletic scholarship for the University of California at Berkeley, she’s also experienced a stress fracture in her foot. "I’ll be laying in bed at night and I’ll start to feel pains in my shins and stuff and I’ll be like, ‘This probably isn’t a good sign.’"

"I can see where a doctor would say that [running a marathon] is not the best thing for your body," she adds. "It’s not like you run and you feel great. You feel like crap for a week afterwards. The whole next day you’re walking like an old lady. I couldn’t climb any stairs for a day."

By his count, Boston Marathon medical director Marvin Adner has run 50 marathons. He doesn’t run them anymore because his knee hurts him. Arthur Siegel, who calls himself "marathon-friendly," ran the Boston Marathon every year for 20 years, starting in the 1970s. He calls Boston the "Holy Grail, a badge, a rite of passage." He stopped, he says, because "it just got to be more than my body could handle."

On the flip side, Children’s Hospital’s Brian Fitzgerald has never run a marathon. "Run it?" he snorts. "It’s a long way to drive. You kidding me? I’ll catch them as they fall across the finish line."

And fall they do. Of the scene in the triage tent at the finish line in Boston, Adner says, "Ever seen ER?" Siegel also works in the tent. "People can get delirious," he says. "They can need IV fluids."

There are wheelchairs, people collapsed, blood, says Adner. "The [injured runners] look like they’re dying. They’re just tired. But with fluids and rest and cooling, they get better really quickly." He adds, "It’s fun."

And talk of death, seizure, even permanent skeletal damage isn’t compelling enough to dampen the enthusiasm of many a distance runner. "I think I’ll probably do it as long as I can," says Lombardi. "As long as my body lets me."

She knows it hurts. She ices away. But she’s not going to stop. Runners ready?

Nina Willdorf can be reached at nwilldorf[a]phx.com