The world heavyweight champion, who defends his titles against Alexander Povetkin at Wembley Stadium on Saturday, said that he had visited laboratories of sports manufacturer, Under Armour, to see how Ronaldo maintains his body for peak performance.
“Cristiano Ronaldo did a body test. He is 33 but has the body of a 21-year-old. You have to preserve your body,” explained Joshua, 28.
“I could go in there and knock out Povetkin in a round or two, but then there is the eight weeks of -intense sparring, doing 200 rounds, you have to protect your body.”
Eddie Hearn, the fighter’s -promoter said of Joshua: “When he went to Under Armour, it blew his mind. For a British fighter, Anthony is by far the most advanced in terms of training facilities or what he does. These scientists looked at his sleep and rehab. Joshua’s drive is the challenge to improve himself.”
Joshua has also been studying the regimes of some of the greats – Floyd Mayweather, who had 50 fights undefeated, Manny Pacquiao, who claimed world titles in multiple divisions, and the -current standout fighter in world boxing, Vasyl Lomachenko, a double Olympic and three-weight world champion.
“I am learning to -adjust my life. When I watched a Pacquiao documentary, he trains when his body is ready. It looks lazy, but you’re still getting the same amount of work done and in a better way.”
Hearn added: “He is obsessed with improvements. He knows when he has to eat, sleep and nothing will get in the way of that.”
Joshua has said that he wants another decade in the sport. Hearn is sceptical, though. “His desire at the moment is deeper than ever, but he might not fancy coming up to Sheffield and into camp anymore.”