(Photo: Geisel)

Shelton, already a star in the world of ultrarunning, which typically involves 50-mile routes on varying terrain, and Ghelfi are sort of birds of a feather when it comes to a shared pragmatic viewpoint on running and competition. Both have run marathons, but are also interested in pushing boundaries and exploring other avenues within the genre.

The two have been training and gearing up for the 219-mile trek, and last weekend ran the Chart House/Footloose 5K/10K, even though the two acknowledged that road racing isn’t their focus at the moment. “I like switching it up,” Ghelfi said. “Jenn said she wanted to do the Muir and I didn’t even think about it. I was in.”

Shelton added that the JMT has been a preoccupation for her especially. “I tried to do it last year, and didn’t make it,” she explained. “My partner [runner Connie Gardner] was fabulous, but she was puking by hour four … NOT the way you want to start!”

She and Ghelfi, both Ashland, Ore., residents at the moment, haven’t even known each other that long, only having just met at a Sacramento road marathon last year. Originally from Redding, Calif., Ghelfi was a high school runner, whose parents also ran, but didn’t get addicted until college. “I was a college runner, and we had strict rules, and were sort of contained in our own college bubbles,” recalled Ghelfi, 23. “You build aspirations in college; in high school, most of the time you don’t really get it yet.” A Mt. Shasta trail guide, these days Ghelfi said he’s better at road racing, but really likes trails.

Shelton, 28, hails from Virginia, and prior to setting records in several of the most demanding American ultramarathons, attended the University of North Carolina, where she also played on the rugby team. In 2006, she gained more notariety traveling with Scott Jurek, Christopher McDougall and several other ultrarunners in McDougall’s well-known book on the sport, “Born to Run.”

She says that she finds marathons more challenging to run than ultramarathons, but still runs them, qualifying this year for the 2012 U.S. Olympic Marathon Trials. “I was psyched to do it, even though I didn’t have a chance in hell,” she quipped. She holds the record for the fastest female 100-mile trail race. “I’m not a snob … I like all kinds of running.”

Ultramarathon is still in its infancy, according to Shelton. “There’s no real, hard training ethic yet,” she said. “As soon as you prove something, someone does something else that works.”

As for their run on the JMT, Ghelfi thinks that type of run is even more undefined. “No one knows how to train for 220 miles,” he stated. “I don’t think anyone cares,” Shelton added with a laugh.

Still, both say they’d rather run the JMT than any other event they can think of. “Running on a hot road in the middle of summer isn’t logical,” Shelton said. “Running the ridgeline in the prettiest part of the Eastern Sierra, that’s rad.”

Will they set any records? “Maybe … it would be nice to hold a record, even if it gets broken later, which it probably will,” acknowledged Ghelfi, who at one time held the record for the run up Yosemite’s Half Dome. “If we can advance some knowledge and influence training, that would be aweseome.”

The pair plan to run the 219 miles ideally in 72 hours (3 days) or less. The record so far: 3 days, 7 hours. Shelton has her sights on the women’s record, which is 3 days, 23 hours and was previously the overall record. “It started out at about 7 days, so it’s come a long way,” she noted.

“With trails, you don’t have race fees and you set your own calendar,” Ghefli explained, adding that getting a permit for Mt. Whitney (the run’s starting point) is a requirement. “We’re not doing it on a full moon, but at least we’re not doing during my [colorful expletive] period,” Shelton joked.

They’ll have support teams at about five different points along the way, and Ghelfi said water bottles will likely have to be refilled at least 100 times.

The two estimate they’ll make that goal if they average 3 miles per hour consistently, with only minimal time to rest, and about 1 hour of sleep each day. “In ultra it’s called RFP: relentless forward progress,” Shelton related. They will also rely on their team chemistry for emotional support during the highs and lows they expect during the run. “Alone, there’s a lot of temptation to quit, so having a partner is a plus,” Shelton indicated. “If you’re bitter or frustrated, leave it on the trail.”

What are their strengths?

“I’m great at climbing,” Ghelfi opined.

“I’ll be holding up the bus on that part, but I can’t run slow; I’ll have to work on pacing myself,” Shelton confessed. What’s their biggest challenge? “Not getting hurt,” according to Ghelfi and Shelton. “That’s a deal breaker.”

Shelton and Ghelfi plan to start on Aug. 14. Follow their progress via tweets from Shelton on Twitter @SheltonJenn.