By Adam Shergold
PUBLISHED: 05:30 EST, 14 February 2013 | UPDATED: 06:07 EST, 14 February 2013
Inspiration: Oscar Pistorius says a silent prayer to his late mother, Sheila, before every race and credits her with encouraging him to take up sports as a child
Oscar Pistorius credits his mother, Sheila, as one of the greatest influences in his life and a driving force behind his success.
She died at the age of 42 - when Oscar was 15 - after suffering an adverse reaction to medication after being wrongly diagnosed with hepatitis.
Sheila and husband Henke made the decision to amputate Oscar's legs when he was just 11 month old, after he was born without a fibula in either limb.
She wrote a letter to her son before the operation with a message he could digest when he was older.
It read: 'The real loser is never the person who crosses the finishing line last. The real loser is the person who sits on the side. The person who does not even try to compete.'
Sheila and Henke were advised to amputate before he was old enough to walk, as this would be less traumatic.
By the age of two, Oscar had his first pair of prosthetic legs fitted and had mastered them within days.
An enthusiastic sportsman, Oscar played water polo and rugby competitively in secondary school. He also played cricket and tennis, took part in triathlons, was an Olympic club wrestler and a keen boxer.
In June 2003, after shattering his knee playing rugby, he was advised by doctors to take up track running to aid his rehabilitation.
Before every race, Oscar says a silent prayer for his mother, who encouraged him to play as many sports as possible.
Winner: When Oscar was amputated at 11 months, his mother Sheila wrote him an inspiring letter saying that the 'real loser' in life was the one who 'does not even try to compete'
Tribute: Pistorius has his mother's date of birth and death tattooed on his right arm
Pistorius and his father Henke in a photograph from 2005
Happy child: A young Oscar Pistorius in the family home
She died on March 6, 2002, a date Pistorius has tattooed on his arm along with her date of birth.
In an interview with Sportsmail before the London Olympics, Pistorius said: 'She was very special to us. She was very cool; a very hectic, free spirit. She didn't really comply with much and had a very carefree approach to life.
'She didn't take anything too seriously. she wrote us hundreds of letters and taught us hundreds of things and never made decisions for us.
'Those are important lessons, when you try to do things sometimes and you don't succeed and you give up, and you never really know what the potential could have been if you had stayed dedicated to something.'
And he paid tribute to her again after becoming the first double amputee to compete in the Olympic Games at London 2012.
After qualifying for the semi-finals of the 400m, he said: 'I thought about my mother a lot today. She was a bit of a hardcore person. She didn't take no for an answer.
'She always said the loser isn't the person that gets involved and comes last but it's the person that doesn't get involved in the first place.'
Tragedy: Pistorius has been charged with murder after allegedly shooting girlfriend Reeva Steenkamp