Rooney loses patience with media critics
England's forward Wayne Rooney takes part in a training session at the Urca military base in Rio de Janeiro on June 16, 2014 during the 2014 FIFA World Cup tournament - by Ben Stansall
"Sometimes (I) wonder what the press are getting at," the Manchester United striker wrote in a post on his official Facebook page.
"I said from the start I want to do everything I can to make sure I'm ready for these World Cup games and as part of that I was doing extra training a week before the squad joined up.
"That's exactly what I did yesterday, my own extra training, because that's what I wanted to do."
Rooney's status as an automatic pick has come under scrutiny after his subdued display on the left side of England's attack in their opening World Cup defeat by Italy on Saturday.
He trained with the substitutes from that match at England's Rio de Janeiro training base on Monday, prompting newspaper reports that he may be dropped for his side's second Group D game against Uruguay on Thursday.
However, the Football Association released a statement on Twitter late on Monday explaining that the 28-year-old had "requested additional training".
England coach Gary Neville believes that the fixation with Rooney's status merely reflects a national obsession with star players.
"Our country loves it, creating a drama around one player," Neville said during a BBC podcast.
"This time it's Wayne Rooney, but that comes with the territory of being an important player in a big nation. I've never known there not be an obsession around one player.
"It was (Paul) Gascoigne from 1996 to 1998, (David) Beckham from 2000 to 2006. From 2006, it was Rooney and Beckham. Now it's Rooney in 2014.
"Unfortunately -- or fortunately, because he is a big player -- this time it's Wayne Rooney.
"You can't get him to do a light day's training. That's his character. He just wants to play every second of every day.
"He has an enthusiasm for football that is incredible and he's been like that since the moment I played against him when he was a young Everton kid."