New research has found Aussie kids are only ranked in the middle of the pack when it comes to aerobic fitness.

Australian kids are also-rans in the fitness stakes compared to kids from other countries, new research has found.

Based on the results from a 20-metre shuttle run test, the study, led by the University of South Australia, compared the results from 1.1 million children aged from nine to 17 from 50 countries.

Aussie kids ranked 35th for aerobic fitness, well behind the fittest from Tanzania, Iceland and Estonia.

“If all the kids in the world were to line up for a race, the average Australian child would finish somewhere in the middle of the pack,” lead researcher Professor Tim Olds said.

The research has been published in the British Journal of Sports Medicine and offered an insight into general levels of community health.

“Cardiorespiratory fitness is an excellent indicator of good health and there’s evidence showing that kids with high fitness levels are healthier and tend to live longer,” fellow lead researcher Grant Tomkinson said.

“One of our key findings was that income inequality — the gap between rich and poor — was strongly linked to cardiorespiratory fitness, with kids from countries with a small gap between rich and poor having better fitness.”

Coming on the back of Australia's disappointing performance at the Rio Olympics, Dr Tomkinson said the study also showed there was some work to do to support the next generation of elite athletes looking for Olympic success.