By Alan Baldwin
AUSTIN, Texas (Reuters) - Lewis Hamilton declared himself fully fit for Sunday's U.S. Grand Prix after a sore foot ruled the triple Formula One world champion out of tire testing last week.
"I am 100 percent, feeling great," the Mercedes driver assured reporters on Thursday. "I basically had an injury that I've been carrying generally all year long, in both feet. Just induced by running.
"Unfortunately the physio said that it just takes a lot of stretching and it just heals over a long time," he added.
The triple champion was spotted limping at a factory celebration of his Mercedes team's third successive constructors' championship and did not attend the Pirelli test in Barcelona on Wednesday as had been scheduled.
"At the time I woke up in the morning, I was feeling quite a lot of pain the day before, and it hadn't diminished," he explained at the Circuit of the Americas.
"The most important thing was to be fresh for here and feeling better for here. This is actually the first week that it's felt good."
Hamilton needs to win the remaining four races and hope German team mate Nico Rosberg, who is 33 points ahead of him, slips up along the way.
The Briton clinched his third title in Texas last year, winning after Rosberg made a late mistake and gifted him the lead.
Rosberg has won nine races so far this season to Hamilton's six, but the Briton has a much better career record in the Americas.
"America has always been a good hunting ground for me. I've been out here for a week already, so I'm looking forward to fighting again," Hamilton told reporters.
(Reporting by Alan Baldwin, editing by Martyn Herman)