Mirna Ortiz, a 25-year-old single mother, is on the path to realising her dreams of Olympic glory after qualifying to compete at the London Games this year. 

One of eleven brothers and sisters, the Guatemalan athlete trained and competed in racewalking for just three years before quitting at the age of 15 to help support her family. 

But in 2009, a coach who saw her race when she was a teenager tracked her down. He helped convince her to leave her job at a supermarket and return to training.

David Mercer reports from Guatemala City.