Jenny Simpson was probably the last kid on the playground anyone would have picked to become a world champion runner.
Although she was active and full of energy, she struggled with a series of respiratory illnesses throughout her childhood. She took to equestrian pursuits early on, competing in everything from dressage to show jumping to western pleasure.
It took a move from Missouri to Florida in third grade to ignite her running career. Coming to a new school mid-year, a physical education teacher suggested she get involved in an after-school cross country program to make friends.
Most of her memories of the club involve running laps around the schoolyard and eating popsicles.
"That third grade physical education teacher had no idea what he was starting," said Simpson, the reigning world champion in the 1,500 meters.
Despite the relaxed nature of the program, at the end of the school year all the children competed in a 1-mile time trial. That race set a series of events into motion that would define Simpson's existence.
"I ended up getting second place and my parents always thought that was the spark that made me want to continue to run," said Simpson, who will be competing at the world championships, which begin Saturday in Moscow. "I wanted to come back and win the next year and that got the ball rolling."
That spark ended up making way for a slow burning flame that wasn't fully ablaze until years later. It was a high school coach with an eye for talent, named Jay Getty, who put the bug in her ear that she could truly be one of the best.
"Having someone other than your parents reach out to you and tell you that you could be great was a big turning point for me," she said.
Indeed, Simpson's first win finally came her sophomore year at Oviedo High School on the track of Astronaut High School in nearby Titusville, Fla.
That is when Simpson fell hard for running.
"After that I wanted to win the conference meet and then the state meet and then run against athletes from all over the country at Foot Locker Championships," she said. "Running was really the first place I identified a positive competitive outlet."
For Simpson, it was a complex relationship with the sport from the very beginning.
"There wasn't one day or one run, I just learned to love the different aspects of the sport over time," said Simpson, who set numerous NCAA records on the track at Colorado. "The days I didn't want to get out and lace up my shoes, it was the camaraderie of my teammates. ... Other days, I'd revel in the hard physical work."
Those are the same things she loves about running today.
"I sometimes think to myself, 'Who would have ever guessed I'd be here,' " she said. "I didn't come from a family of athletes and I wasn't that kid who said I wanted to be a professional athlete when I grew up. I was just looking for a way to make friends in third grade and it ended up being a huge part of my identity."