Ms Southorn's cycling career started in fairly innocuous fashion, taking it up to keep fit and get away from injuries suffered in horse riding.
"I was encouraged to join the cycle club and it just grew from there. I swapped riding horses to riding bikes.
"I fell off the horses a lot but fell from my mountain bike more. After too many concussions I stuck with the road bike and got into track racing, travelling once or twice a week to Manukau Velodrome.
"Track racing is exciting and frightening at the same time and I love the type of training with a mix of gym, road riding and track."
It was track racing that took Ms Southorn around the world on her bike, competing in the C5 Paralympic category at the 2004, 2008 and 2012 Paralympics.
The C5 category is for cyclists with the least impairment, including single amputation and minimal neurological dysfunction. Ms Southorn is missing her left hand. The trip to London for the 2012 event rates as a major highlight.
"After 12 years of progressively getting faster and two other Olympics I was finally rewarded with an Olympic medal," she said.
"The friends I have made through my Olympic journey are friends for life, we all have a common understanding of what it takes to get to the top in any sport."
But it's off the track she has made her biggest impact. From 2004 to 2013 she was a sports ambassador for SPARC (now High Performance Sport New Zealand) and visited schools across the country and took on speaking engagements to encourage young people to achieve in sport. She continues to visit schools in a voluntary capacity.
From 2014 to 2017 she cycled from Wellington to Auckland as part of the BDO corporate annual fundraiser, raising between $15,000 and $20,000 each year for community charities. Giving back has always been a source of enjoyment for her.