Stung by being dropped from Australia's Test team for a lack of pace, Peter Siddle believes he is now back to his best and will be out to prove it against Pakistan in Wednesday's first Test here in Dubai.

The Victorian cut out running and upped his calorie intake, adding some 5kg of muscle which has allowed him to reclaim the lost 10kph that cost him his place in Australia's third Test win over South Africa in Cape Town.

"I'd trained too hard and that combined with the amount of cricket we were playing and the intensity we play at, it probably did affect me," said Siddle.

"I had to change the training routine a little bit and I'm seeing the benefits at the moment. Hopefully they continue."

A key part of that change to his training routine was cutting out his sprint work and regular 6km runs, which helped him to bulk up.

"I am still feeling as fit as I ever have," said Siddle. "I think that stint in England where I was still playing (county cricket with Nottinghamshire during the Australian winter) has given me a good base and I have a lot of kilometres in the legs to keep ticking over.

"I stopped running when I got home (from England) but I played 11 first class games in 90-odd days over there so the fitness side of things is no issue.

"I have been bowling loads in the last few months so that does not change a thing."

Siddle said he had felt "pretty fatigued" in South Africa and while it hurt to be dropped it was also a blessing.

"It's probably helped me think about a few things I need to work on and change and get right. I think I'm back to where I want to be."

The right-arm-quick bowled 16 overs in Australia's first innings in the field in the warm-up match against Pakistan A in Sharjah, and seven in the second. The pace was up, and the accuracy that so often frustrated Kevin Pietersen into throwing away his wicket was in full effect.

Siddle said he was drawing inspiration from Mitchell Johnson who has credited an extended rest from cricket – enforced by a toe injury – with reviving his speed.

"He (Johnson) bowled for five years straight before he hurt his foot and he was down to bowling high 130s or low 140s at that stage, for a bloke who bowls mid-150kph.

"For him to have that break and freshen up mentally and physically and come back and bowling the best he has just shows, a bit of rest here and there, work on a few things, change a few things and get that rhythm back … I am feeling good and that’s what it is all about."

Siddle said Australia's wicketkeeper Brad Haddin had told him the pace was back and the ball was carrying through with his old zip, and he has also received the backing of the team's coaching staff.

"Sidds bowled pretty sharp, I thought his speed was good, which is up a lot on South Africa I think," Craig McDermott told cricket.com.au.

Darren Lehmann also backed Siddle, saying he had been "really impressed with him".

"Siddle has done a lot of work with our bowling coaches and our strength coaches to make sure he's getting the power back he needs," added Lehmann.

And the strapping fast bowler had a word for those who pointed to his vegan diet as responsible for his drop in pace.

"Everyone thinks you have to eat meat but I am the one who hasn’t been injured in the last two and half years so that probably explains something," said Siddle.