Cristiano Ronaldo conditioning secrets revealed as Manchester United icon turns 37

Cristiano Ronaldo will continue playing at the top level into his forties - the man who helped shape his trademark physique claims.

Having sealed a sensational return switch to Manchester United last summer, the five-time Ballon d'Or winner has scored 14 goals in 23 appearances.

United are set to take on Middlesbrough in the FA Cup at Old Trafford tonight (8pm).

On the eve of his 37th birthday, that fourth round showdown will mark Ronaldo's last game as a 36-year-old.

However, according to former United power development coach Mick Clegg, who worked with the Portugal star during his first spell at Old Trafford, there is no reason why Ronaldo won't continue for several years yet as he also outlined his 'genius' when it comes to maintaining elite physical condition.

During an interview with The Mirror, he said: "Cristiano is a genius, an absolute genius. He learned a lot in his early days about how to manage his body. Not just physically, but mentally, emotionally and spiritually.

"He's got a knowledge of nutrition and he knows how to balance things. He knows how to balance his food and is consistent in everything he does.

"The only person I've found as consistent was Ryan Giggs, which was why he played on until he was 40. Cristiano will want to go beyond the 40 mark. He'll be hoping he can play until his mid-40s.

"He needs to know everything about himself. If he has a niggle, he'll want to know what that niggle is and will talk to people he knows and trusts about it."

Clegg added: "With Cristiano, everything is done with precision. When he goes to the dinner table, he doesn't just eat any old s***. He eats what he knows is going to put what he needs into his body.

"His focus all the time is on getting things right. It's