Portuguese knee surgeon Jose Carlos Noronha has hailed Cristiano Ronaldo's "unique" physical qualities and revealed the Ballon d'Or winner's interest in the science behind his achievements.
Ronaldo, 31, has been a regular patient of Noronha, who has treated a host of top internationals, including Angel Di Maria and Pepe.
The Real Madrid star is yet to play for his club in 2016-17 after suffering a torn collateral ligament in the final of Euro 2016.
But the star forward has remained relatively injury-free throughout his glittering career and is likely to be back in action soon for Zinedine Zidane's side.
"He has a unique physique," Noronha said in an interview with Tribuna Expresso.
"It's like those cars that last millions of kilometres without any fault.
"I have known Ronaldo for 11 years, since he was in Manchester. He had some minor injuries and asked for advice.
"In addition to having a great character, he is an athlete who fulfils all that is required to maintain a physical and psychological form to the fullest, from food to sleep and fitness."
Ronaldo - perhaps unsurprisingly given his famously sculpted physique - takes an interest in nutrition, according to Noronha, who also praised the national team captain's influence on his younger team-mates.
"He is a scholar and occasionally he asks me if there are new scientific articles that you can read on food and other topics," he said.
"He is an example - exceptional. It is remarkable the support he gives to the younger players in the team, to integrate them and take away any fear or shame to be there next to a monster."