Luis Martins, a former youth coach at Sporting Lisbon, has revealed the commitment Manchester United star Cristiano Ronaldo showed in his formative years.

Martins fondly recalls Ronaldo scoring from his own half in a youth match against Estrela de Amadora, or finding the youngster in the academy's weights room at 11pm the night before a crucial Under-16 game against Benfica and having to admonish him for doing some extra strength sessions.

"I had to tell him that I didn't approve of this, on the night before the match," Martins told the Sunday Herald. "He told me that it was necessary to be extra fit before the game, and he needed extra strength. I had a very angry row with him, but in the morning against Benfica, he scored two goals and we won 5-0, so there was no problem. But the first years which Ronaldo had at the academy were not easy for him because he had some problems adjusting to the culture. Madeira is a very different culture."