Cristiano Ronaldo naps five times a day and it's one of the biggest reasons behind his success

Cristiano Ronaldo takes up to five naps a day and they last 90 minutes each, according to a sleep expert.

The Manchester United striker is insanely dedicated to his craft and is one of the world's best thanks to his state of the art routines.

Nick Littlehales worked with Ronaldo during his time at Real Madrid and broke down how he gets his forty winks in an interview with The Independent.

Ronaldo sleeps in the foetal position and is obsessed with marginal gains when it comes to personal performance.

He explained: "Anyone who has ever worked with Ronaldo knows that if you have a discussion in the corner of the room, he will come over and ask what you are talking about.

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"I was invited to Real Madrid when Carlo Ancelotti became manager [in 2013]. I was standing on the edge of the training pitch, talking to the Madrid staff, when Ronaldo ran over.

"He had been training all day and you would have expected him to run straight to the dressing room for a shower but he asked what we were discussing.

"He was interested in what I was trying to do because as an athlete he has always invested in himself.

"From what I have learned from working with him, Ronaldo is not interested in fad diets, he is not interested in copying others. The only thing he is concerned with is: does it work for him?"

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Littlehales also worked with legendary United manager Sir Alex Ferguson, but that was after Ronaldo's departure in 2009.

Ronaldo has since made his way back to Old Trafford but is seeking a move in the final days of the summer transfer window.

The 37-year-old wants to play in the Champions League and let the club know of his desires early last month.

No official bid has arrived however and agent Jorge Mendes is looking around Europe for potential suitors ahead of Thursday's deadline.

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United manager Erik ten Hag was asked about Ronaldo's future following Saturday's 1-0 victory over Southampton, which the five-time Ballon d'Or winner started on the bench.

He told the club's official website: "I cannot say that [Ronaldo will leave United]. We plan with him and we stick to the plan and if there are good players available we will strike because we want to strengthen the squad always.

"So we will be alert until the last second of the window."