Australia's Fittest Kid Finishes Solo Ultra Marathon

Jack Sinclair, an 18 yo Queensland lad, is fast gaining a reputation as one of Australia's fittest kids with the completion of his latest endurance effort - a 1,200 km solo run around Tasmania in just 27 days.

Sinclair ran more than a marathon a day for 27 days straight, battling torrential rain, dodging Tiger Snakes and Targa Tasmania cars to complete the run to raise money and awareness for youth mentoring charity Big Brothers Big Sisters of Australia (BBBS).

"Jack's been an incredible supporter of Big Brothers Big Sisters of Australia for a number of years. His selfless acts continue to raise money for the organisation which means he has created a legacy that will ripple out into the community and the nation for decades to come," said Keith Perkin, CEO of BBBS.

Looks can be deceiving with this slightly built, quiet lad who would rank as one of Australia's fittest kids.

At 15, Jack became the youngest person ever to cycle across Australia - 4,500 kms in just 30 days

At 16, he ran his first full marathon

At 17, he won the school 96 km Kokoda Challenge against 66 other teams - breaking the old schoolboy record

Completely unsponsored except for a heart rate monitor from fitness firm Aussie Fit Sport, Sinclair funds his own adventures will all donations going to charity.

"Jack's an inspiration to many, many people and the least we could do is provide him with some gear to make his journey a fraction easier," said Diana Bethune, Marketing Manager of Aussie Fit Sport.

First Thing He'll Do When Finished

After putting his body through 27 days of pain, Sinclair has a simple plan for when he's finished.

"I'll be having a lie down. I may not get up again till about November," he said.

Although he loves cycling and running, he says next time he'll try something that involves a motor.