Despite COVID-19 interrupting her three-peat, the 47-year-old was first across the line in the open female division of the three-day, 208km race.

"I was really excited to win this year as you can never know what is going to happen," Cambourne said.

"I'm 47 years old and the slight hypothermia on day one made me worry about how I would pull up day two.

"But I topped up my salt levels and made sure I got quality sleep and was ready to go again the next day.

"My bond with the canoe guys, who are amazing paddlers who helped me stay upright in the locks each day was a highlight and their support as legends in the field meant a lot to me."

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Although she's always enjoyed being on the water, Cambourne has only competed on the flat water for the best part of a decade. A shoulder injury while paddling a surf ski in 2006, which resulted in a series of operations, forced her to make the transition across from a sport she'd done for more than 20 years.

"When I started paddling 20 plus years ago, my coach at the time said to me 'you will paddle for 20 years and only occasionally will you feel 10 or more strokes in a row where you feel like you have finally got this paddling technique sorted. That feeling will be gone as quickly as it came. It is searching for that 10 stroke feeling that will keep you coming back'," she said.

"He was right. I keep searching for that 20 seconds of feeling awesome - the next day you keep searching for it."

Her transition to flat water saw her join Makai Paddling Club at Burrill Lake, which has played a huge role in helping Cambourne produce personal best times year in, year out.

"Paddling is a very technical activity and for 20 years, I have been fascinated with how tiny little adjustments to paddling technique can result in a change in speed or a change in energy output," she said.

"The sport of ultra-marathon paddling involves ensuring every stroke is about 100 per cent efficiency with as little energy expenditure.

"Most of my ultra paddling events involve holding a heart rate of 140 beats per minute for five to eight hours non-stop.

"The physiology of being able to maintain this keeps me coming back.

"The comradeship you form with other paddlers who are also learning how to keep their bodies doing the same activity also keeps me coming back.

"I know some paddlers in their mid-80s who are doing the same distances.

"It's a sport you can do for many years and it's low impact on your joints."

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To prepare for the gruelling event, Cambourne, who has also won events such as the 404km Massive Murray Paddle, RPM 200, 110km Hawkesbury Classic, Clarence 100 and Myall Classic, used her line of work as an exercise physiologist to her advantage.

"As an exercise physiologist, I have been studying the exercise physiology of human performance," said Cambourne, who works at BrainFit Exercise Physiology in Nowra.

"My interest for years has been brain health and the physiology of brain fuelling, so I apply a lot of the research I read to my own paddling and try out different nutrition approaches that keep my brain alert while also keeping my body at a constant speed.

"I also use a continuous glucose monitor that tracks my body's glucose response while I am training so I know when I need more fuel.

"I spend up to five hours at a time on weekends leading up to the event on my own on our beautiful Lake Conjola and Berringer Lake.

"During these paddling sessions, I listen to the latest evidence-based research on exercise physiology so I get to learn at the same time.

"It's also five hours away from my phone, listening to my own heartbeat, which can be very good for slowing my very busy mind down."

This in-depth training, which always includes directives from her coach Hayley Nixon in South Africa, prepared Cambourne for her assault on the June 12-14 event.

Day one sees competitors, either as an individual or duo, paddle 76km from Martins Bend to Moorook - starting at 6.45am.

"On day one, I got really cold as I took my hat off and couldn't reach it, so for three hours my body was shaking as my head was wet from the cold water on my head splashing off my paddler," she said.

"I felt as though this would be the first time in five years of racing I may get too cold and have to stop as my arms and head were really cold in the slight breeze.

"I had to tell myself, I was warm over and over again for three hours to convince my body I was okay.

"I also sang the wheels on the bus for hours at a time to keep my rhythm.

"What also helped was one of my clients, who is an army veteran, sent me a message the day before saying 'remember when you think you are done, you are only 30 per cent done and you have 70 per cent left'."

After resting that night, a 69km journey from Moorook to Waikerie from 6.45am awaits the participants.

Then on the final day, paddlers get underway from 6am, in the cold and dark, for their 63km voyage from Waikerie to Morgan.

"Each day, the paddle involves a fast hit out paddle to a lock - as paddlers are started in various start times so we all arrive at the lock around the same time," she said.

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"This means the faster paddlers leave last and it's a race to get to the lock.

"At the lock, we all come together again and are lowered to the next level of the river and then the race begins for the next 50 plus kilometres.

"The conversations in the lock are very funny as all paddlers need to huddle together to stay upright for balance as many of our boats are built for speed and very tippy when stationary.

"The following five hours are long stretches of lonely cliffs and beautiful scenery.

"Thankfully, this year was perfect weather but the previous two years I had completed this paddle were windy and cold.

"Not to mention 5-10km stretches into headwinds can take over an hour of maximum effort only to turn the corner for a short reprieve of 1km then back into another 5km of headwinds - it takes a lot of focus."

With that in the back of her mind, Cambourne this year took a slightly different approach of pushing herself more for the first 20km, before maintaining a constant speed for five hours.

"I have practised my nutrition over eight hours, so knew I could hold a constant speed," she said.

"I don't stop at all for the whole race so as long as I stay mentally alert, I had trust in my body to be able to maintain a constant heart rate and as close to constant speed for eight hours - however, you only need to get wobbly and fall out or hit a log and its all over.

"There is very little river flow on this section of the Murray due to the locks so there isn't much help from the river."

After overcoming all these obstacles, in addition to health challenges including heart surgery and only having one kidney, Cambourne claimed line honours for her third Riverland Paddling Marathon crown.

"Win number three showed me I'm now developing into a consistent paddler," Cambourne, who thanked her partner Drew for his invaluable work as her support crew, said.

"I have achieved a personal best in most ultra-marathon races I have entered over the past four years, which is my main goal and then sometimes I even surprise myself with a win.

"I was the fastest single boat overall so I was really happy with that.

"I am learning more about human physiology and my ability to burn fat on my own body rather than use processed food has helped me to feel no pain at the end of each day, which makes my following day of racing a lot easier.

"I also wanted a training and nutrition plan that didn't damage my heart or kidney.

"I have found what is working and it is keeping my speed consistent each year."

Like any top-level athlete, Cambourne is already planning her next competition, which will be a 24-hour event at Lake Burley Griffin in Canberra.

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"I'm aiming to complete the 24-hour paddle, which is a boring 5km lap for 24 hours straight," said Cambourne, who still ranks her Hawkesbury Paddle race in 2018, where in windy, dark conditions she finished the 10-hour race at 3am despite losing track of time and having big fish swimming around her, as her proudest moment.

"I attempted this paddle in 2019 and unfortunately the race was paused at 11 hours due to a bushfire coming through.

"I was feeling good at the 11-hours mark but very mentally bored, so this year I would like to overcome the mental challenge and paddle through the night."

As focused as Cambourne is on achieving her own goals, she is also passing on skills of future paddlers as a Wood Eye Paddling coach.

"I run local paddling lessons in the Shoalhaven and am just completing my paddling coaching qualification on top of my exercise physiology degree," she said.

"This will make me the only female paddling coach in the Shoalhaven area, so I am hoping to attract more young people and more women to the sport of marathon paddling through my Wooden Eye Paddling squads.

"I have a number of fantastic paddlers with neurological conditions in the Wooden Eye squad who inspire me every day."