Olympic 50m free champion Cesar Cielo will race at "99%" during Brazil nationals, the Maria Lenk Trophy in Rio from today, so that he can be at 100% come the London 2012 Olympic Games in July.

World record holder over 50m and 100m from 2009, Cielo told Folha de Sao Paulo on the eve of action that he and the PRO-16 squad he founded and leads, will use nationals to establish whether the plan they have been following is working and worth sticking with all the way to London. 

"I would say that I'm 99% fit here to be 100% at the Games. I'm going to treat it like a world-title final - my target time is ambitious," said Cielo, who added that he would only clip his body hair with an electric razor rather than go for a full shave. "That way I'll feel like there's something saved for London."

So far this year, he has season bests of 21.85 in the 50m and 48.70 in the 100m. With Australian James "The Missile" Magnussen on 21.74 and 47.10, the Brazilian aims to throw back a gauntlet or two - and will need more than 1%.

Part of the PRO plan, said Cielo, is "not going out at night and not making mistakes". He cited "dedication, positive thought, ambition, perfection and excellence" as the group's mantra this season.

The squad had "drive ourselves half mad" in the process of watching diets, sugar intake and the like this season, the sprinter told reporters in Rio. His own mum, Flavia, had been banned from buying anything other than gluten-free products, while the fridge at home has a sign on the door reading "Excellence ... so that I always think before I eat".

Not a bad idea given the events of last year:  Cielo retained the world 50m freestyle title in Shanghai days after a CAS hearing cleared him to race following a slap on the wrist for positive test. FINA had challenged the ruling, believing a six-month ban was warranted, rather than a warning. CAS accepted that the swimmer and three teammates were not to blame for the presence of a banned substance in a food supplement (cross-contamination was blamed) - though for one of the four, the error was registered as a second offence that ruled him out of the water for a year. 

Thiago Pereira joined the chorus, stating that he had never given nutrition that much thought before but the regime he's been under has "made a big difference". Cielo predicted that his teammate would post a big surprise at nationals this week. 

The meet has attracted an international entry, including a squad from Denmark, with world 1500m champion Lotte Friis at the helm, and France's Laure Manaudou. Her partner Fred Bousquet is also on the entry list a month after missing the cut for the London 2012 Olympic Games at domestic trials in Dunkirk.