WE CAME ALONG THE SEA COAST IN A TAXI, away from the airport, the windows open to the warm evening rain as a woman's voice sounded soft and sing-songy on the crackly radio. "And they will be bicycling all over the island," she was saying, "and, oh, yes, they will be climbing the very big hills."

The taxi rounded a turn, its engine groaning a bit as it ground up an incline. We came into a forest, and suddenly the world was green and lush, the narrow macadam road empty of cars and squiggling skyward like a lane in a storybook. The verdant beauty around us was beyond words.

But perhaps you have seen Dominica, a tiny island nation of 70,000 people that sits just north of Barbados and several hundred miles from the Dominican Republic. Dominica played backdrop to this summer's blockbuster, "Pirates of the Caribbean: Dead Man's Chest." The movie is a mawkish lark, and its basic story line — Watch out, Jack Sparrow! Those Carib Indian cannibals are going to roast your pirate bones on a spit! — was offensive to many Dominicans. But as it lingers on the island's mist-shrouded hills, with drums pulsing ominously in the background, the film gets at the spirit of the place: Two-thirds of Dominica is still blanketed in coniferous old growth. There are 365 twisting mountain rivers here and a host of waterfalls cascading down into clear emerald pools. And the land is so cragged and steep that it's almost unfathomable.

Though it is only 29 miles long and 16 miles at its widest, Dominica is home to two peaks over 4,500 feet. The rest of the island is essentially a range of smaller mountains and valleys, and the roads are murderous. There is one paved hill that rises for a steady mile at a 28 percent grade. The Tour de France, in contrast, rarely offers up grades steeper than 10 percent, and almost never goes steeper than 15 percent. Virtually no one travels to Dominica to ride a bicycle.

"And there are three cyclists, you know," the woman was saying now in melodious tones on the radio. "There is John Moorhouse, a very talented bicycle racer who lives in Florida. There is a photographer — his name is Peter — and there is a very famous writer."

John Moorhouse, who is 36, was sitting beside me. A Dominican by blood, he spent his teenage years on the island before moving, in 1993, to Orlando, where he's become a standout in 24-hour mountain bike races, which see competitors looping dirt paths for a full day and night without ceasing. He rides his bike 250 miles a week, and in races he has no qualms about chomping down a whole stick of butter, straight from the wrapper, as he whirs starved and bleary-eyed through the 3 a.m. darkness. Moorhouse works as the U.S. distributor for Scottoiler, a British company that makes bicycle lubrication systems, but he dreams of returning to Dominica one day to guide bike tours. He was now on a reconnaissance mission, and he'd alerted the media by sending out a press release saying that his expedition here was to "conquer" the hills. In an agrarian country aiming to promote ecotourism, his quest was national news.

Behind Moorhouse, photographer Peter McBride, 35, was oblivious to his new celebrity and chatting away on his cellphone. McBride is stocky and ripped, with the rugged bonhomie and tousled good looks of a Patagonia clothing model. Once a member of the U.S. developmental ski team, he now specializes in adventure assignments — in sea kayaking Croatia and backcountry skiing the Republic of Georgia, that sort of thing.

And the "very famous writer"? Well, I had plenty of time to ponder that phrase, since the ride away from the airport, in Melville Hall, to Dominica's capital city, Roseau, is long and winding and slow — marred by potholes so nasty that, at one point, I saw a small tree growing in a two-foot-deep chasm bitten out of the edge of the road.

The "very famous writer" was me.

I AM 42 YEARS OLD, and I ride my bike 100 or so miles a week. I ride almost everywhere – to the grocery store, to the dentist, the nine miles to my daughter's school, even when it's cold and raining outside. But this devotion to biking is a new thing for me, begun only a few months before my Dominica trip, and for two decades now, I've approached exercise with an anxiety that has at times neared an engulfing obsession.

Let me explain. I was an athlete once, too — a distance runner. In college, I could run five miles in just over 26 minutes; I once ran a half-marathon in 1:13. I was strictly mediocre by NCAA standards, but good enough to glimpse in running a delight, a feeling of mastery, that had eluded me as a bony and skittish kid relegated to the "challenged" section of gym class. I could enter an all-comers, all-ages 10K and place 10th or 12th in a field of 500 people, and I lived, as all devout geeks do, with numbers streaming through my skull. I could recite my splits and my finish times from memory, and I knew, to the second, the records set by running's great luminaries. I made sense of the world — and of where I stood in it — through numbers.

But when I was 21, I pulled some back muscles. A minor overuse injury, nothing much, but somehow I was filled with the fear that I would never recover, that I would be no one again. And, indeed, I did not recover. Regularly, throughout my twenties and thirties, I fell into these horrible, claustrophobic episodes, months long, that would begin with a simple muscle pull — a knot in my hamstring, say. I would worry about the pain and brace so stiffly against it that I became like a dry stick waiting to crack. Officially, I had myofascial pain syndrome. My muscles kept pulling, going deep into spasm. I became ensconced in a rictus of pain, and soon that rictus became who I was.

For 11 years, starting when I was 27, I was so afflicted that, if I sat down on a hard chair, my lower back would immediately sing with a hot, electric-like pain — a pain that would persist, after a minute of sitting, for days. Sometimes, with the slightest provocation, I experienced that same stinging pain in my forearms, in the inside of my thighs. I saw a dozen doctors. I was told, at one point, errantly, that I had a certain arthritis — ankylosing spondylitis — and that my lower vertebrae could fuse over time as my neck curled downward, like a question mark. I wrote standing up. I dined at restaurants standing up.

But one winter the sitting pain simply disappeared, leaving behind a constellation of intermittent and less keening muscle aches. I spent $60 on a used bike then, to see if I could ride a couple of miles day after day. I could, and over time I bought a new bike. I rode faster, and I found myself excavating a dusty and long-dormant version of myself that I'd almost forgotten.

I was there on Dominica as a reporter, sure, and all I had to do was follow John Moorhouse around for three days and 110 miles. No one was going to kill me if I rented a car. But there was no way I was going to do that — no way. As I sat in the taxi, I resolved to wrestle up every hill, even though my back problem had flared up again. My hip was in pain, injured a week earlier, while I was stretching. I had not ridden in almost a week.

LUCKILY, A MINOR CRISIS SHOOK THE HALLS of governance in Roseau: The airlines misplaced my bike while it was en route to Dominica; my bike was at large. Dominica's minister of tourism, Yvor Nassief, got on the phone at once, to hound American Eagle. "Mr. Donahue," he said to me in somber tones, peering across his expansive desk, "we apologize. This is inexcusable."

Secretly, I was delighted. I had a whole extra day to stretch out my hip, and so I did what I often do when I feel the muscle fibers inside me are screaming at one another: I wandered around on foot, alone, aimlessly, trying to wriggle out of the cage of self-consciousness and find peace. I followed the Roseau River downhill from our hotel, near the village of Wotten Waven, and then cut sharply right, uphill, onto a narrow, steep tree-shaded road. Then I consulted my map.

Even though Dominica was a British colony until it attained independence in 1978, the names of the villages all around me were French — Giraudel, Massacre, Fond Cani, Laudat — and the people in the hills nearby often spoke Creole at home. The French held Dominica briefly in the 1700s — and then stayed on, even after the British Navy defeated them. They built churches and schools and, with the English, brought in ships full of African slaves to work on sugar plantations. But the Europeans never really vanquished Dominica. The land was too mountainous to cultivate easily. The plantations were fragmented; the slaves kept running off into the woods to cook up bloody rebellions.

Today, Dominica remains untamed. There is only one fast-food chain restaurant on the island, and the airlines have to corkscrew down into Melville Hall, cutting hard and circling low in small planes, so as to angle onto the short runway squeezed between mountains. Neither Club Med nor the Sheraton has, as yet, elected to subject its clients to the indignities of landing here, and even Lonely Planet, which has published guidebooks on 135 countries, has so far shied away from producing a Dominica book.

I was there on Dominica because it's still wild, and I was after a sort of animal joy that you cannot get in a gym on a StairMaster. I wanted to feel the ragged beat of my heart in a place that resounded with its own green vitality. So I kept climbing — and came, eventually, to a sign for Trafalgar Falls, three miles away. A driver stopped to offer me a lift, and I hopped in and rode up a couple of absurdly steep pitches as the car pulsed with house music. Then the guy reached his home, still far away from the falls, and I walked on until I found myself nearing a tall, dreadlocked man who held a machete loose in his hand. He was not wearing a shirt, and his pecs and abs rippled with a sinewy grace.

"You like Dominica, mon?" he asked.

I said I did. We strolled together to a small roadside shack. I bought him a beer, and we chatted a bit. Then I walked away. The air was steamy and the hills around me teeming with life — with mango, guava and passion fruit growing wild — and I kept picking the guavas up off the ground and eating them.

In time, I went back to the hotel. My bike had arrived, express, and with an Allen wrench I put it together. I tested the brakes, adjusted the seat. And then, along with Peter and John, I went out for a warm-up: down the hill into Roseau, the crickets chirping in the night all around us.

THE NEXT MORNING, we floated through Roseau again, riding in a pack. We cut left along the coast, through the villages of Loubiere, Pointe Michele and Sibouli, and drivers heralded us with their horns, having seen us on television. "Ah," said one woman, "you are the big cyclists!" We came around a bend, and John pointed inland at a rocky peak in the clouds. "See that?" he said. "That's where we're going." He spoke almost wistfully; we were retracing the routes of his earliest adventures.

Moorhouse grew up in the suburbs of Boston, but his mother is a native Dominican, and when he was 14 the family moved back to her homeland. His dad, a machinist, bought him a motorcycle, and he used it to ramble all over the island. "I remember going into the Syndicate area, up north, to ride on a network of paths that looked out onto the sea," he told me. "I went into remote mountain villages, and there was no electricity. The people spoke Creole. I got to know the island by riding my motorcycle."

Moorhouse had a BMX bicycle back then, too, and he rode without fear. When I stepped into a cafe in his old village, Paix Bouche, one man put down his rum, then demonstrated how, long ago, John would carefully stand up on his moving bicycle, placing one foot on the seat and one on the handlebars, so as to "cycle surf" down the street. "John Moorhouse," he said with thick admiration. "Madman! Professionnel!"

In 2002, Moorhouse did try to launch himself as a pro athlete. He quit his job at a bike shop and created a five-man pro squad, Team 24, but his income — $4,000 here for a race victory; $500 there for wearing an "Ellsworth Bikes" shirt in a magazine photo — was sporadic. "Unless you're Lance Armstrong," he said, "it's really hard." Until very recently, he was working a string of odd jobs — installing highway guard rails, for instance. In between gigs, he would spend seven to 12 hours each day crawling the Web and posting ads — on eBay, pinkbike.com — for his Dominican cycling trips.

For Moorhouse, this trip was crucial. Our expedition needed to shine, and he rode — we all rode — with fervor. Once, John rampaged along with one tire high in the air for the length of a football field. Later, as I sailed downward toward the base of an approaching climb, he shouted encouragement — "Momentum is your friend!" — and then flailed past, standing up as he pumped on the pedals.

At the top of one hill on that first afternoon, I took my pulse. My heart was going at 192 beats per minute.

WHEN THE PAIN IN MY BACK WAS AT ITS WORST, I spent years exploring alternative medicine, visiting chiropractors, acupuncturists and, at the nadir, an "energy worker" who beseeched me: "Breathe! Breathe! Deep belly breaths now." Always, I felt a certain tacit judgment coming down on my head: My inner Vince Lombardi, they agreed, was an aberration of post-industrial Western society — and it needed to be curbed, if not utterly purged.

I expected that Dominica would deliver me the same lesson. I knew, in any case, that it had some crucial lesson to impart. The people there are healthy. They subsist on fresh fish and homegrown vegetables, and they walk the hills. A myth prevails: Locals believe that they are the longest-lived people in the world. In fact, Dominica's premier advocate for centenarians, a publicist named Alex Bruno, claims that there are now at least 15 Dominican citizens more than 100 years old, and the whole island embraces a woman named Ma Pampo, who died in 2003 at the reported age of 128, as a sort of national saint.

Before I visited the island, a friend wrote to me, speculating on Dominican longevity. "I think there is something about the pace of life there," she said, having just visited, "about the lack of stress and the uncomplicated fishing communities. There's time for a slow beer in the afternoon. And it rains a lot, so you seek shelter and sit it out."

Biking the island, I saw that life in Dominica is often languid and calm. Once, for instance, I came heaving to the top of a pass and the first thing I encountered was a thin, sixtyish man sitting on the ground, his back against a tree as a lone bony cow behind him picked at the grass at the edge of a cliff. The man acknowledged me with a subtle nod and then resumed staring off into the distance, saying nothing, a study in energy conservation.

But there is a hard edge to Dominica, too. The soft-spoken Rastafarians hustle as they hoist crates of bananas into their trucks, and when their tempers flare they sometimes draw out their machetes and duel. In the roadside cafes, where old men gather to play dominoes, they slam their tiles down onto the table, sharply, as an expression of manhood.

And when I had the chance to meet 100-year-old Louisa Benoit, she was sitting up in her living room, her hair and her wardrobe impeccable, as she sewed a child's dress for a festival. Benoit has been working steadily as a seamstress since the 1920s, and I told her that she seemed pretty tough. "You bet I'm tough," she growled. "I can't walk, but you get down on that floor right now and I'll fight you. I'll beat you right now."

As dusk fell on our first day of riding, we climbed into a high mountain village, Bellevue Chopin, in the rain — and then began swooping downhill. It was almost dark out, but I heard something beside me. Two kids, maybe 15 years old, were riding down with us on ancient BMX bikes. Unlike us, they had no helmets, no lights.

We kept descending, picking up speed. We were going 25 miles an hour, then 30, then 35. Then I heard a scraping and crunching sound at my side. Sparks danced from the asphalt, and I watched one boy belly slide over the wet, rubbly pavement as his bike rattled beside him. I figured that he had broken a leg, at least, so I stopped, seized by a parental concern.

But by now the kid was already standing. He'd gotten up instantly, as though doing that might erase his brief lapse of poise from the record. I could do nothing but offer a lame admonition. "You really, really have to be careful," I said.

The kid did not want to be hassled. "We live here, mon," he said. He resumed his descent, ahead of me, and it was only then that I realized that he had no brakes on his bike. He was slowing and stopping himself by pressing his sneaker down on the top of the rear tire. Later, I would learn that this was how all the kids braked in Dominica.

WE RODE ON, ALONG THE SOUTH COAST IN THE DARK. We had been on the road several hours by now, shedding gallons of sweat, and Pete simply cracked. His muscles seized with cramps because he was so depleted of salt. Suddenly, he was almost mincing on his pedals and lagging behind. He folded for the day; he hitched a ride from a fellow named Sam. And in the village of Petite Savane, there were only three people on the street — John, me, and an old man, seriously intoxicated, who came running out of a cafe, rum in hand, to chase after us and offer support as we started in on our expedition's most grisly ascent, Morne Paix Bouche, which rises at a grade averaging about 20 percent. "Original!" the drunken man bellowed, expressing homage in Creole. "Original, mon!"

I started climbing. At first, I was aware of Sam's SUV lurking on the road above me, the beam of its headlights pivoting as it wound through the switchbacks. Soon, though, I was aware only of the pavement around me, and the roadside bushes and grass illuminated by my small light. Then the world narrowed even more. Everything peripheral was annihilated, and I existed, for maybe 10 minutes, in a bliss of focus and pain. With each stroke, I felt my pedals pause and creak at the top of the crank, and I felt my front wheel kicking up, off the pavement, each time I got to a switchback and cut straight at the fall line. My spit was viscous and tasting of blood, and low down on the stem of my brain I felt a certain glimmering satisfaction. "I'm doing this," I thought. "My muscles are working."

I kept climbing — one switchback, then another. But then, maybe 70 percent of the way up the hill, I looked up for a split second and saw Sam's car two or three switchbacks above. The headlights seemed distant, like candles guttering in the high nook of a cliff, and I knew suddenly that there was no way. It was not merely a matter of will; I was simply not strong enough to pedal to the top of this mountain. I got off my bike, and John passed me, huffing "good work, good work." Then I walked on, secretly ecstatic. I was standing, I knew, on a sweet island in time. Soon enough — within the next decade of my life, certainly — I would need to reconcile with my body growing older and weaker and slightly more brittle. I would need to find music in going slow. But right now — for a moment, at least — that onus was on hold. I had just pushed myself harder than I had pushed in 20 years, and nothing had broken.

BUT OUR TRAVAILS WERE NOT OVER. We kept butting up against a problem: John remembered the roads only hazily, and each time we arrived at the base of a hill, he tended toward optimism, saying things like, "This one really isn't that bad." Right out of the blocks on day two, we hit a hill that John described as "short." A mile later, we were still climbing, straight up in the breezeless humidity.

"How far to the top?" I asked a woman out taking a stroll.

"Continue like so," she said with warm cheer as she waved her hand vaguely, "and you will soon be reaching your destination."

A half-mile later, another passerby: "You have almost arrived, my friend."

About a half-mile after that, we neared a man who had dreadlocks and wore a red, green and yellow knit hat. "How much farther?" I asked.

The man took a long drag on what appeared to be a cigarette, and then spoke. "Yeah, mon," he said.

Later that afternoon, in the village of Rosalie, we got to the base of a hill that John described as "two or three miles long." It actually rolled upward for 5.4 miles, and when Pete arrived at the crest, lugging, as always, 40 pounds of camera gear, he was cramped up again, and he could speak only one word with conviction: "Taxi!"

John and I pressed on, up switchbacks through the villages of Gaulette and Salybia, and as evening fell John surged ahead. I was alone, and at two different turns in the road men began running up hill, after me, the instant they caught sight of my white skin and my shiny bike. "Money," one man implored.

I was now on the Carib Indian reservation, where the unemployment rate is about 70 percent, and I had no game plan for such appeals. I just pedaled hard, dodging anyone who might beseech me for cash, until I reached our hotel.

AT THE CARIB TERRITORY GUEST HOUSE, I was hit with a strange, serendipitous surprise: The place would play host, that evening, to a series of four boxing matches. A ring had been set up on the patio outside the kitchen. There were ropes knotted to the patio's concrete columns, and around the columns, there were foam pads. The floor of the ring was terra cotta underlain by concrete.

The matches would pit the Dominican National Team, a middling player in the boxing stronghold that is the Caribbean, against an underdog — the Kalinago boxing club, whose members all hailed from the Carib reservation, bearing a long history of oppression.

The tan-skinned, almond-eyed Caribs are the Indians Columbus encountered when he first reached the Caribbean in 1492. Once scattered throughout the archipelago, they now possess a single land reserve, where many live in simple one- or two-room huts.

The Kalinago boxing team does not train in a gym. Instead, the boxers steel themselves by lifting rocks pried out of the earth. They spar on concrete, usually without benefit of face masks or gum shields. And on the night I was with them, they had to wait for the national team, which was inexplicably an hour late. They stood by the roadside in tank tops, lithe and lean and mean as snakes.

I waited nearby and talked to the Kalinago coach, Augustine Frederick, who is 32 and the sole Carib on the Dominican team. Frederick is a tiny man, a featherweight, and he is stoic and quietly earnest. He said: "They gave me their word. They will come." He said: "This is the first time my fighters have ever competed, and the national team, they feel like they will walk all over us. But you watch: We have been training a full year for these fights. We have a surprise for them."

The national team arrived, finally, and the fighting began: a lurid blur beneath the hot white flood lights. The Caribs fought barefoot, and the first bout was an ungainly thing, with the boxers elbowing and shoving and tangling their arms. But the true drama happened outside the ring. There were 60-odd spectators — nearly all Caribs, and among them a guy who'd chased after me — and everyone was delirious as the proprietor of the guesthouse, Charles Williams, did the play-by-play over a staticky microphone. "Oh yes!" he yelled, his words rolling into a jazz scat. "Oh yes! Something's happening here! Something's happening here!"

Williams, 56, is the chief of the Caribs and a controversial firebrand. Last year, he divided his tribal council when he noisily decried "Dead Man's Chest," whose directors hired hundreds of Caribs to play scantily clad cannibals. He noted that there's no archeological evidence proving that his ancestors were cannibals, and he lambasted every Carib who took $95 a day for film extra work. "Shame on us," he said in a press release excerpted by many U.S. newspapers, "that for a few dollars we are betraying our flesh and blood."

As emcee, Williams did not hide his loyalties. He rejoiced when the first fight went, on decision, to the Caribs and then again when the next Carib fighter victoriously split the lip of his opponent. All night he kept crowing: "Go Carib boy! Go Carib boy!" Spare and agile himself, he kept dancing into the crowd and handing the mike to his friends, and they echoed his banter — albeit, with less poetic aplomb. "Very good," one man intoned, "very good, well done."

The referee called the third fight a draw, and then the fourth fight began — a stocky Carib bruiser, Julien Valmond, against a much taller, rail-thin boy with jet-black skin, a kid so delicate-looking that I winced as he stepped into the ring. Within 30 seconds, Valmond had the kid on the ropes. At the back of the patio, he was efficiently pummeling the boy's face. The boy crumpled to the concrete. He stayed down for the count. And then the crowd flew into a frenzy, released, it seemed, from 500 years of hard luck. People leapt high into the air, their arms stretched above them in victory. They toppled white plastic deck chairs and danced. They chanted — "Julien! Julien! Julien!" Frederick, the coach, stood nearby, calmly beaming as he said, "I knew they would do their best," and Williams spouted a stream of unintelligible euphoria into the mike. Listening, I remembered what one old woman had told me as we set off on our journey: "You will have a fine time," she said without elaborating. "This is an open country."

Now I understood what she meant. Dominica is open-hearted: An unrehearsed humanity prevails. Restraint and tense hesitation and the walls between people all dissolve in the sweltering heat.

I wasn't used to life being so freewheeling, so loose-limbed. Generosity exists here in the United States certainly, and it can flash out at the most random moments — when you're stuck by the side of the road with a flat tire, say, and some stranger comes along with a jack. But still so much of daily life feels corporatized, digitized: Minute to minute, we are awash in phrases such as, "May I be of further assistance to you?" and "Press one for more options." We are never too far from a Mini Mart whose sterile fluorescent lights burn all through the night.

It can be cold and alienating to live in such a landscape, and an uncertain person can find myriad reasons to retreat, to go inside his shell. And that is what I did often when the muscles in my body were knifed by pain. I functioned so that there was not much perceptibly wrong with me, and nominally, gingerly, I stayed in shape, taking walks, swimming laps in a pool. But I conceived of myself as broken. Quite often I refrained from the most basic activities — climbing down a few flights of stairs, say — in fear that I would spiral down into worse, more intractable muscle inflammation and pain. I held the pain around me like a case, a shield, and I cultivated a hurt contempt for the world as the pain fed on itself and worsened.

Now, ringside, I felt the chanting shake through me: "Julien! Julien! Julien!" Eventually, someone kicked on the stereo, so it blasted loud reggae, and then we all flowed outside and milled about on the grass, chatting, saying nothing of substance, as we lingered out there in the dark.