Here he recounts his gruelling training schedule ... and meeting pop star Gwen Stefani at the Grand Canyon.

"The first of two weeks of training in the USA have been both exciting and exhausting. I am one of 12 Australian Swim Team members training in the USA in preparation for the 13th FINA World Swimming Championships to be held in Rome starting July 26.

This group, which includes Olympians Stephanie Rice and Brenton Rickard, is based at the high altitude training facility at the Northern Arizona University in Flagstaff. We're training at an altitude of 2102m (6891 ft above sea level), where the oxygen is less dense, thus making it harder to breathe.

Last week I swam over 75 kilometres in 12 pool sessions. We started the week lightly but built up the intensity as we adapted to the altitude.

This was a tough week for me as I am in what's called the "endurance phase" of my preparation, 8 weeks out from competition. At the World Championships I will be competing in the 400m, 800m and 1500m freestyle races as well as the 4x200m freestyle relay.

For these events, I need to train for longer and a lot more frequently than those swimmers who just race 50m or 100m distances so as to build my aerobic base. Training at altitude helps that.

The week ended with our team having the Sunday off training as a recovery day so we travelled to the Grand Canyon just one and half hours away. It was absolutely huge, a magnificent sight and so much bigger than I ever realised.

When it started raining during our visit we headed for shelter and were lucky enough to meet up with the pop singer Gwen Stefani who was there with her family (and entourage). She politely declined our photo request but we were all very excited to see her anyway.