Champion marathoner Meb Keflezighi says he only started running to get an A in 7th grade gym class

Meb Keflezighi, the winner of the 2014 Boston Marathon, is defending his title on Monday.

Keflezighi, who also took home a silver medal in the men's marathon in the 2004 Olympics, has become one of the most famous runners in America - the first American to win the Boston Marathon since 1983.

In an interview with Business Insider while promoting Epson's Runsense GPS watch, Keflezighi said his career as a runner began rather simply - he wanted a good grade in gym class.

After Keflezighi and his parents moved from Italy to the United States in 1987, seeking a better opportunity for education, Keflezighi said he was good at soccer, but he didn't even know running was considered a sport.

"It was an accident, it happened by accident," Keflezighi said. "It was just seventh grade, a P.E. teacher said if you run hard, you can get an A or a B - if you don't run, you get a D or an F."

Keflezighi said he was also motivated because if students ran a mile in under six minutes and 50 seconds, they could get a T-shirt from their junior high school. Keflezighi finished in five minutes and 20 seconds.

"It got me an A and a t-shirt."

Keflezighi added, "My running was discovered. Who ever would have thought that would change my life?"