Wladimir Klitschko believes Anthony Joshua needs "big muscles" to make himself confident and does not want any excuses when he topples the IBF champion at Wembley.
The 41-year-old is just weeks away from his heavyweight world title fight against Joshua on April 29, live on Sky Sports Box Office, and has started probing for mental weakness in his younger opponent.
Joshua's physical power has brought him 18 knockouts in his perfect professional career, but Klitschko compared him to a 'CrossFit champion' during a stinging analysis of the 27-year-old British fighter.
Klitschko said: "AJ has a lot of energy, he's young, he wants to be explosive, he has these big muscles that bring him confidence and he just wants to demolish people right in front of him. That's what it is, it gives him a lot of confidence, but did you hear about boxing being a sweet science?
"Every person would have got these big muscles. It gives you confidence and you really can smash if you hit the heavy bag, or the person in front of you. Boxing is sweet science. The vicious boxers were conquered.
"I have a lot of respect for Anthony and what he is doing, his commitment, his physical ability. He can box, he can lift weights, he can be strong, he can train.
"He can be a CrossFit champion actually, a CrossFit world champion. I think he has great capability of it. CrossFit became really popular and there are a lot of boxers doing it. But CrossFit is not boxing."
Klitschko could not resist a dig at former opponent David Haye, who famously blamed a broken toe for his one-sided points loss, and hopes his fellow countryman will not make a similar complaint.
"I don't want to hear 'oh it was too early for him,' or 'of course Klitschko cannot dominate, because he is over the hill,' and all of this.
"AJ wants to become billionaire, as he said, which is a great ambition. But it's a challenge with a lot of question marks.
"I look forward to it and I think it's going to be a great event and I wish both of the fighters will make it injury free, so there is no toes, no other issues which could be in the way. I'm really looking forward to this challenge."
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