Salazar says he originally planned only to tell the Cains to find a local coach who could implement small changes. The Cains asked him to speak with Mary, and that arrangement has grown into a full athlete-coach relationship, though much of it is conducted from afar during the school year. The Cains pay for all training expenses, in case the family decides that Mary will run for a college team. "We want to have all her options open," says Charlie. Freshly minted U.S. 100-meter champion English Gardner and Oregon Project distance runner Jordan Hasay, both of whom competed for Oregon, are already both pushing hard for Cain to matriculate in Eugene. Any college that recruits Cain will most likely have to agree to let Salazar remain her coach while she runs in its colors. It is possible that Cain will only attend college while running professionally, as 2012 Olympic 200-meter champion Allyson Felix did a decade ago. "It's a different path," says Felix. "Definitely mixed emotions. I feel like I missed out on the college experience, but I'm grateful for the experiences I did have."
Salazar was blown away by Cain's speed and skill set. "She's inherently very, very fast," he says, and his program is geared toward creating the blazing finishes that are necessary in modern racing. Salazar says Cain has maxed at 61 miles for a week; leading up to the nationals, she and Moser ran a workout that included 10 200s in an average of 27.1 seconds with a 200 jog recovery at 5,000-foot altitude. After Cain's high-school-record 15:45.46 in the 5,000 meters on June 8, she did two 400s in 59 and 57 seconds.
The specters of burnout and physical maturity hang over Cain, as they do for all young female runners; there is a long list of those who have gone fast early—though none as fast as Cain—and struggled later. Lauren Fleshman, 31, a Stanford graduate and two-time U.S. 5,000-meter champion, is frequently queried on her website by young women seeking to deal with physical changes that slow their careers. "As a female, it's a long road," says Fleshman. "When you're young, your hormonal profile is more like a guy, more testosterone and less estrogen. Your strength-to-weight ratio is incredible. But you can't fight nature forever. Very, very few women escape a few years of fighting their bodies. Mary is an incredible talent. Probably works her butt off. She's going to have a great, long career, and she will have some challenges and injuries along the way."
Fleshman says that Cain will be insulated in part by her association with an elite training program, where she also has access to the Oregon Project's resident sports psychologist, Darren Treasure (who sat in on Cain's interview with SI but did not interrupt). "There's an element of protecting her," says Treasure. "There's going to be a day when she has a bad race. We want to help teach her skills to deal with that and to fulfill her potential."
Salazar says, "The [phenoms] who struggled, most of them eventually got better. But Mary is already at such a higher level."
Charlie puts it much more simply. "As long as she comes off the track smiling," he says, "that's all we care about."
Mary was struck by a nasty case of nerves in the 24 hours leading up to her race last Saturday; she had fought similar battles before many high school races. She does not, however, fear systemic failure. "I'm not one of those people who is scared, like, Ooooh, I'm going to burn out," she said last weekend. "And even if this is the best year I ever have in my life, I've experienced a hell of a lot. But I don't believe that's what this is. I'm surrounded by people who know what they're doing. I know I'm not done and I'm not meant to be done."
It was late on a Sunday morning, and there was a flight home to catch, to step back into the world of the suburban teenager. Cain rose from her chair, nodded her head and raised one hand ever so slightly. "Oh, yeah," she said. "A nerd in Sports Illustrated."