At each meet this season, Marra has taken Eaton on his own to the pole vault pit and set the bar at a challenging height.

“Big meet, average meet, whatever,” said the veteran decathlon coach. “I say, ‘O.K., Ashton, this is the Olympic Games, this is your opening bar, let’s go get over it.”’

Most recent simulation: last month at Stanford University in California. “We went there on purpose because Stanford can have crosswinds and be a tough place to pole vault,” Marra said.

“But anybody who thinks an Olympic stadium won’t be a tough place to pole vault doesn’t realize the winds in the circular nature of a stadium aren’t consistently at your back,” he added. “So I said, ‘Ashton, you’re in London, you’ve got a great meet going’ — I painted some sort of scenario — and then, ‘Here it is, first attempt.’ Boom, he went right over it. And I said, ‘Ashton, whatever you do the rest of this meet today, you’ve accomplished what we wanted to accomplish here.”’

Although Eaton is just 24 and has only recently acquired a taste for decathlon history, Marra, 64, has been around the sport more than long enough to have an indelible memory of what happened to Dan O’Brien in 1992. Despite holding the world record in the decathlon and despite a “Dan and Dave” advertising campaign built around his rivalry with his compatriot Dave Johnson, O’Brien did not qualify for the U.S. Olympic team after failing to clear a height in the pole vault at the national trials.

Disaster is never to be excluded in a draining event that presents its competitors with two days and 10 distinct opportunities to crack. But Eaton is the decathlon’s fastest-rising star, a smooth-talking, big-leaping prodigy who broke the 8,000-point barrier in only his sixth competition and is now preparing to take aim at 9,000 points as one of the favorites for the London Games.

The other leading men — the reigning world champion, Trey Hardee, and the reigning Olympic champion, Bryan Clay — are also Americans, which means that a U.S. sweep of the decathlon medals in August is hardly out of the question, although they must first safely negotiate the U.S. qualifying trials next month.

“We can collectively do it; we just have to stay healthy and just all be there,” Eaton said of the Olympic sweep in an interview last week. “The specialness will happen if we’re all there prepared to accept it.”

Eaton, a former National Collegiate Athletic Association champion from the University of Oregon, is the youngest and least decorated of the three but is considered by many athletics aficionados to have the biggest upside and the potential to break Roman Sebrle’s world record of 9,026 points, set in 2001.

Clay, married and a father of three young children, is trying to rebound from injuries and make his third Olympic team at age 32. Hardee is 28 and had his own pole-vault nightmare become reality at the 2008 Olympics in Beijing, where he failed to clear a height. But Hardee, a commanding presence at 6-foot-5, or 1.96 meters, and 210 pounds, or 95 kilograms, has recovered in style: He won the last two world outdoor titles and defeated Eaton last summer in Daegu, South Korea, where they finished first and second but hardly on acrimonious terms.

“Trey helped me a lot, a lot, a lot in Daegu,” Eaton said. “When I was down on myself, he kind of said: ‘Hey, I no-heighted at the Olympic Games. You’ll get through it. Just keep going on.’ But at the same time, we’re trying to beat each other as well.”

Hardee trains in Austin, Texas, where he competed for the University of Texas. Clay trains at his alma mater, Azusa Pacific University, near Los Angeles. Eaton trains in the track and field hub of Eugene, Oregon, as part of the Oregon Track Club’s elite program.

Marra coaches Eaton and his fiancée, Brianne Theisen, a Canadian heptathlete who is still competing for the University of Oregon as a fifth-year senior. She and Eaton share a house in north Eugene, about a 10-minute drive from the track. Their wedding is set for July 2013, shortly before the next world championships and well after the smoke from this angst-and-hope-ridden Olympic year has cleared.

“The Olympic Games is like the biggest event in our life right now and then once that is completed, then our wedding will be the biggest event, so that will be cool,” Eaton said.

They would represent different nations in London, but Eaton said there was no doubt that he and Theisen were feeding off the other’s Olympic obsession.

“Sometimes we’ll have bad days on the same day and just be so frustrated that we’ll have to try to do something else,” he said. “But sometimes we both have really good days, like the other night we were talking really late and excited about javelin because we started talking about feeling it and how certain things are supposed to be.

“So I think it would be way worse if I had, say, a normal job and I wasn’t athletic and I didn’t know anything about track or the Olympic Games and just cared about her because it was her thing,” Eaton added. “It’s so much better because we know how it feels: ‘Oh I got so lactic on those 300s, and I missed my time.’ It’s just different.”

Marra, who has never before coached a couple exclusively during his long career, said the two also feed off each other’s results, with Eaton winning the long jump on his final leap in a recent meet in Texas after delaying his attempt to watch Theisen clear a personal-best 6-foot-2 in the high jump.

Eaton was raised in Bend, Oregon, by a single mother, with whom he remains exceptionally close. He has yet to win a major global decathlon title. But in March in Istanbul, he won the world indoor championship in the seven-event heptathlon, crushing his own world record with help from the longest long jump ever recorded in a heptathlon: an 8.16-meter leap that would have placed him fourth in the individual long jump.

The throws have been his relative weakness, but he has already recorded personal bests in the javelin and shot put this season. Still, the emphasis has been on making his strengths even stronger with the focus on the 100 meters and long jump, which happen to be the first two events of the decathlon.

“If you start a decathlon out with those high performances and start it out consistently, I think you put a lot of people on their heels,” Marra said. “They start pressing and thinking: ‘Oh my God. I have got to catch up to you in the shot put or the high jump or something.’ And when you try to catch up and pull yourself out of your rhythm, then all of the sudden it’s like swinging the golf club too hard. It’s going to go far but it will go straight into the woods.”

Marra, who has been coaching decathletes since the 1970s, is intent on helping Eaton avoid the woods in London. That explains the pole-vault play-acting and also explains him encouraging decathlon greats of the past to reach out to Eaton. Those include Rafer Johnson, the 1960 Olympic champion, who had an extended meeting with Eaton this year, and O’Brien, the 1996 champion, who has much in common with Eaton and talks to him more regularly. Both are from Oregon and from mixed-race backgrounds. Eaton’s mother is white; his father, with whom he has had little contact, is African-American.

Along the way, Eaton has been learning more about the decathlon’s rich past in the United States, where it was once a signature event before the decline in track and field’s media footprint. At the Olympic trials next month in Eugene, the organizers will honor the 100th anniversary of the first Olympic decathlon, won in 1912 in Stockholm by the American Jim Thorpe.

“He was a little bit clueless on the history, but now all of the sudden Ashton Eaton is picking up on it, which is good,” Marra said. “It’s good to know who went before you and maybe where you’re going.”