Desert High

In precise 10-minute intervals, Frank follows a run-eight-walk-two program. He's stopwatch-serious, giving his mates a 30-second warning and a countdown to each stop and start. They run mostly in silence, marking the passing of desert time by Frank's warnings and by the long minutes it takes to get from one medical checkpoint to the next, about 6.2 miles down the course. Pete tends to chomp at the bit of Frank's time schedule, so, to distract him from racing ahead, Frank assigns him the task of leading the trio up all the hills. Six hours, 7 minutes and 50 seconds later, the three cross the finish, notching 15th place overall and posting a comfortable 45-minute lead over the Chileans, who finish 23rd. In the end, the Aussies follow Frank's run-walk program with ease. "It was hot," Mike reports afterward, "but we just got it done."

On the night after Stage One, two members of the Chilean team -- Juan Encina and Pablo Lambert -- stride over to Trifecta from the tent next door. In Spanish, Pablo congratulates Trifecta on the day's win. Juan is a compact, muscular man who speaks little and bounces lightly as he walks. He runs a 2:26 marathon (the men's qualifying time for the 2008 U.S. Olympic team is 2:20). Pablo, Juan's longtime running partner, is the opposite: tall and long-limbed, with a thick salt-and-pepper beard, boisterous and partial to sweeping hand gestures. He says his personal best marathon time is 2:45.

The two don't know much about their third teammate, Matias Anguita, who has close-cropped dark hair and an unassuming vibe. "Our manager put him on our team," Pablo explains. He says that Matias is younger and slower, a 3:30 marathoner. Then he shakes his head as he laments that Matias's shoes don't fit, adding that he's concerned that the younger runner's pace is dragging them down. "Big problem for us," he says.

Pablo's competitive spirit is as palpable as Frank's fierce determination. The similarity is no surprise to sports psychologist and Temple University professor Frank Farley, who has studied ultra-athletes for most of his career. "No question they're a different breed from the rest of us," Farley says. He's even coined a term for people like the elite runners, mountain climbers, skydivers and others who seem addicted to challenge: "T-type personalities." T is for thrill-seeking. "It really comes down to a thrill," Farley says. "They tire quickly of everyday things, and their only remedy is to take on the next challenge, hoping for more stimulation."

He and other psychologists note these athletes' defining characteristics: They're independent thinkers. They're methodical about goal-setting. They believe they control their own successes or failures. They thrive on novelty. They're energetic and often innovative. Many are entrepreneurs.

THE RUN-EIGHT-WALK-TWO PLAN CONTINUES TO WORK SMOOTHLY for Trifecta on Day Two. The morning begins with 3.7 miles through an anomalous knee-deep stream along the bottom of the stunning Atacama slot canyons: red rock sliced by centuries of water erosion into slits so narrow that it's rare to get full sun at the bottom. The water slows everyone to a walk. Then there's a brutal, dusty climb to a ridge, followed by a steep descent down a sand dune -- all of which, in wet shoes, is a recipe for blister disaster.

The vistas distract the Chilean team enough for them to lose the course, turning down the wrong side of the ridge, as Matias's feet succumb to blisters. They lose 40 minutes in the valley below, which is enough to give Trifecta a solid lead.

It's not easy to concentrate on minutes and strategies instead of the grand surroundings of the Atacama, but Frank does his best. When they're not on the course, the Trifecta men spend almost all of their time in the tent, which they share with three other runners. Outside, a central campfire crackles (the temperature drops precipitously at night, to a median April low of 36 degrees). Many runners gather round to eat, exchange race gossip and rehash the day's run. But Frank, Mike and Pete stay curled in their sleeping bags with their feet up on little stools. They look like brightly colored inchworms in traction.

The tent is the nylon equivalent of a football-locker-room-cum-freshman-year-dorm. The floor is littered with half-drunk water bottles, discarded bandages, food wrappers, sweat-laden socks and other stray gear. It's common to see one guy slicing open his blisters with a Swiss Army knife six inches from where his tentmate is eating his rehydrated beef stroganoff dinner out of an aluminum pouch. The men are a raucous bunch, bantering about pro wrestling or how much they would pay for a cheeseburger and fries. They also talk strategy and size up competitors. But they don't speak much about their lives outside the race. If they mention wives or girlfriends, it's usually in reference to how they might charm them for permission to run the next marathon. And they hardly mention the backdrop for their adventure. The majestic Andean peaks to the east and the lofty dunes that bake below appear to have made little impression.

BUOYED BY THEIR TWO VICTORIES, Frank, Mike and Pete are caught off guard when Day Three tests their unity. The Chileans shoot out from the starting line, and Frank works throughout the morning to keep his teammates from chasing them. "All we gotta do is keep up with them, Frank," Pete says. "Dude, that's not the plan," Frank chides him playfully.

The Chileans appear at the first checkpoint surprisingly early. When Trifecta comes into the checkpoint a full 15 minutes behind its rivals, the men's faces betray their worry. They're still ahead overall, but the Chileans are closing in today. By afternoon, the wind has picked up, and the dust tastes metallic. Heading up a particularly high dune about an hour from the finish, Pete breaks down, sobbing.

"I told Frank and Hully [Mike] I was done, I'm sick of this [expletive], and I'm going home tomorrow," Pete says in their tent later that night. "Those dunes were killing me. ... But Frank and Hully more or less told me to shut the hell up. I guess I needed that."