Olympic champion Steve Hooker says he's making secret, ground-breaking changes in a bid to return to the top of the pole vaulting world.

But the Australian, finally healthy again after an injury-cruelled 18 months, says expectations of defending his Olympic crown are "unwarranted".

Hooker knows his dodgy left knee could again cause problems at any moment.

"In some ways, I'm going back to square one," Hooker said in Adelaide on Wednesday.

"I have got a good idea of what I want to do in terms of a technical model.

"But just in terms of having the confidence in my body that it's not going to break down, having the confidence in my take-off, in my run-up, and feeling my rhythm on the runway - it's completely back to square one.

"It's a tough process and not the ideal process to be doing at the start of an Olympic year.

"But I feel like, given I'm healthy, I have got plenty of time to do it."

The 29-year-old was working on "new technical stuff" in training.

"I think we are breaking new ground in what we're trying to do," he said.

"It is just a bit of a different focus in what I'll be thinking about during the jump than probably what I have been thinking of in the past."

Hooker refused to elaborate.

"It's a secret," he said.

"I can't tell you that, then everyone will know.

"If it's breaking new ground, why would I give it away?"

But Hooker said he would stick with the changes.

"After the last year and a half being injured, it has not been easy getting back into it," he said.

"It is just a lot of hard work at the moment, a lot of persistence, and trying and get things back in order.

"All I want to do right now is stay healthy and jump as much as as I can, just so I have every opportunity to get back in the best shape for London.

" ... But I have also got to be aware that this is an injury that (could) come back at any time."

Steve Larkin
AAP