Born into grinding poverty and with a degenerative eye condition which left her almost totally blind, Terezinha Guilhermina first became aware of her athletic abilities when fleeing a school bully in her home city of Betim in Brazil.
Despite her apparent disadvantage, Guilhermina easily outpaced her much older would-be assailant and, as fear mixed with exhilaration, she inadvertently found her true forte in life.
"I love to run. I feel free and complete," the three-time Paralympic gold medalist told CNN's Human to Hero series.
"The feeling of moving fast is just magical, it's wonderful."
Guilhermina may have been blessed with natural talent, but the handicaps she faced on her journey to track and field stardom would have defeated most mere mortals.
Coming from a family of 12, her mother died when she was just nine and the children were often left to forage for leftovers just to feed themselves.
"We didn't have much to eat, our diet was always poor," the 34-year-old recalled.
Despite her visual impairment, Guilhermina was forced to attend a regular school -- "I suffered from bullying because I wasn't normal" -- and was in her early 20s before she completed her education.
Still harboring a dream to excel at sports, the impoverished Guilhermina enrolled on a disability project being run by the Betim city council, focusing on swimming and running.
"I found an association that had sports for the vision-impaired. I joined and started to compete."
She initially chose swimming because she didn't own a pair of running shoes, but her sister, who worked as a maid, said "here, take mine."
Guilhermina may have had a pair of hand-down trainers and a coach who encouraged her to compete in her first race, but her visual handicap left her at a further disadvantage.
"I had to train when no one was around because I had no guide," she said.
So for fear of obstructing other runners, Guilhermina took to the track when it was deserted.
"I had to train at the hottest time, which was from 12-2 p.m. because there was no one around. I would run and run until I did 40 laps (16 kilometers)."
Existing on a diet of flour and sugar, living in a house where there was no real shelter from the rain, only an incredible inner will to succeed kept her going.
"I said I wanted to be the best in the world, I thought if I could make it, I would be able to change my future, to change my destiny," she said.
"I would push myself to the limits. I would do 70 laps and barely eat."
Guilhermina started taking part in local road races with the aim of making money to fund her activities and buy basic foodstuffs.
"The first money that I earned made me believe that I would be able to realize all my dreams," she said.
"I won 80 Reais ($40) in a street race, and stopped in a market to buy a yoghurt that I always dreamed of eating since I was little."
Her ability came to the notice of Brazilian Paralympic officials and she was selected to compete in the 2004 Games in Athens, over the distances of 400, 800 and 1500m.
Categorized as T11 for athletes who have no functional vision, Guilhermina was able to run with a guide, but the athlete nominated to run with her proved of little use.