``She just loves it,'' said her proud mother Cath Marson.

``It's not about winning, she values the teamwork and the fun.''

The nine-year-old sports machine not only does running and cycling but also plays soccer for Camden Falcons, competes in physical culture and is a squad swimmer at the Atlantis Aquatic Centre at Smeaton Grange.

Now the year 4 pupil is stretching for the 2010 Sanitarium Weet-Bix Kids TRYathlon which hits Sydney's Olympic Park on Sunday.

The event aims to set a world record as the largest under16s triathlon series on the planet.

She loves sport so much that she travelled to Canberra in March last year on her birthday to compete in the event after missing it in Sydney. ``She just likes the fun of it, she's really athletic and (with the triathlon) she gets to put all the sports she likes together,'' Cath said.

Caitlin will compete in the 7-to-10 age group category cycling three kilometres, running 500 metres and swimming 100 metres. She will join 2800 children statewide 14,500 nationwide for the triathlon to get youth active, with no placings or times being recorded. Paediatrician Christine Bennett said: ``More than half of Australian children are overweight or obese, which is very concerning. We're committed to improving the nation's health by fostering better fitness and nutrition.''