Mexican-born U.S. track athlete Leonel "Leo" Manzano is making his final preparations for the London Games, confident that his Olympic-sized heart will lead him to his best-ever time in the 1,500 meters.

Manzano stands just 5 feet 5 inches and is typically the shortest competitor in his event but he also packs a secret weapon: a heart equivalent to a person more than 6 feet tall.

In tests carried out in 2008 at the University of Texas' Human Performance Laboratory, scientists found that Manzano's heart can consume 82.2 milliliters of oxygen per kilogram of body weight per minute, a capacity that few athletes worldwide can match.

"That was when I realized I have a Ferrari engine in the body of a Ford Pinto," the 27-year-old middle-distance athlete joked.

He maintains, however, that his over-sized heart is not the product of a "genetic advantage" but rather the result of hard work and dedication to the sport his whole life.

"I really wasn't born with a big heart ... I had to work for a long time and with a lot of sacrifice to get this heart, which has helped me achieve a lot of my victories," Manzano said.

A professional runner since 2008, Manzano will compete in his second Olympics starting Aug. 3 after winning the U.S. Olympic Trials in his event with a time of 3:35:75. He will be looking to improve on his first appearance at the world's biggest athletic showcase, having failed to reach the 1,500-meter final four years ago in Beijing.

Born in Dolores Hidalgo, a city in the central Mexican state of Guanajuato, Manzano emigrated to the United States with his parents at the age of four and says he feels "very excited and very proud" to represent the Hispanic community at the London Games.

"I feel very proud to be one of the Hispanics with the opportunity to represent the United States, but also likewise many Latin American countries," the athlete said.

Manzano said he also has a special bond with his homeland even though he moved away at a very young age.

"I feel as though I still have a connection with the people of Mexico and that I also represent them. The United States is my home and I wouldn't change that for anything, but my roots are still in Mexico," he said.

Although he says his running talent is innate, it was not until he began training and competing 15 years ago that he discovered his true potential.

"Like any path, getting to this moment hasn't been easy. It's taken a lot of work, effort and dedication."

He pointed to his titles in the 1,500 meters at the NCAA Championships in 2005 and 2008 and more recently at the 2012 USA Indoor event in Albuquerque, New Mexico as victories that have marked his career.

But Manzano said the road back to the Olympics has not been free of obstacles, noting that a hamstring injury at the 2011 IAAF World Championships in Daegu, South Korea, cost him his chances at that event.

"Every day's preparation is an effort, but we got through (that setback) with work, new routines and more training time," he said.

Manzano's "big heart" also has given him the opportunity to work with the Texas Heart Institute on a campaign aimed at creating awareness of the need to care for that vital organ.

"It's something we need in the community, especially with Hispanic people with heart disease, high blood pressure and diabetes. We have to provide them the information they need to have a healthier heart," he said.

The Olympic athlete also is giving back to the community with initiatives like the "Manzano Mile," a running event he hosts in Austin, Texas, for all ages that seeks to promote a healthy lifestyle. EFE