"Sophie was doing gymnastics from about 12 months. When she was about three, we were messing about on a rugby pitch and she caught the ball naturally.
At one time it looked like she was going to be quite good. But when she was six, she went to a summer camp and said she fancied doing some judo. She really enjoyed it and it went from there.
When Sophie was playing mixed rugby (between eight and 12), the girl was usually put on the wing. But Sophie played scrum half and captained the boys' team.
She was a fantastic tackler and her intelligence and aggression, along with her natural ability, have shone through in all the sports she has done."
But Cox, who returned to the sport in 2010 after a five-year break, remains confident in her own ability.
"I've come back for a purpose," the Kent-based player told BBC Sport. "There's only one reason why I've put myself through the intensity, the training, the lifestyle changes - it's to get a medal. I know I'm capable of taking a medal."
It was back in 2005 that Cox, realising she had fallen out of love with judo following a poor showing at the Athens Games, announced her retirement at just 23.
"I had done an Olympic cycle up until Athens, so done two or three years at the top with that pressure and really going for it.
"But I didn't do as well as I wanted to in Athens or at the 2005 World Championships and there was a lot of pressure on a personal side.
"At the time I probably didn't appreciate judo for what it was. It was a very small world, I felt a bit trapped."
Cox escaped to Thailand where she taught children English.
"I'd never experienced that culture and country before. I didn't plan on staying there past four weeks and ended up staying for four years.
"I found things went back to basics. It was completely different from the material, commercial world I'd been living in. Everything was simple. Nice weather, nice food, nice people. Everything made sense," Cox added.
It wasn't until a couple of years into her new life when she began coaching judo that Cox felt the urge to get back on the mat herself.
GB Judo's Olympic medals
1972 - 1 silver; 2 bronze
1976 - 1 silver; 1 bronze
1980 - 1 silver; 1 bronze
1984 - 1 silver; 2 bronze
1988 - 1 bronze
1992 - 2 silver; 2 bronze
1996 - 0
2000 - 1 silver
2004 - 0
2008 - 0
"There was nothing like that feeling. I had it in my bones, in my blood. I had done it from such a young age. There was this feeling that something was missing.
Despite not competing at an elite level for five years and moving down five kilos to the -52kg category, Cox was pleasantly surprised when she returned to the British senior squad.
"It changed me individually, I'm more aware of what I'm doing," she said. "I'd come on so much in terms of being a judoka. A lot of that is to do with the time I'm able to spend thinking about things on the mat, looking at what I'm doing rather than just hustle and bustle."
Cox must now wait to find out if she has done enough to earn one of 14 host nation places that will be given to the British squad.
"A lot of people don't see the strength in depth so many countries have," Cox explained. "Britain doesn't necessarily have that, so just one or two medals is a tough target to get.
"There is a new structure at the top. They've come in and made the changes that they had to. That poor result at the World Championships [last year] flagged up that something definitely needed to be done."
"I believe on the right day we've got players who can outperform anyone on that level. At least three or four."
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