Tyson, 54, will meet fellow icon Roy Jones Jr in an exhibition bout in Los Angeles on September 12 after posting impressive videos of his preparation over the past few months.
Joshua said at a Sky VIP event: "You see a clip on social media and you think: 'He's back in action, he's fighting fit'.
"But it's like an old-time footballer doing a crossbar challenge!
"Tyson hitting pads with ferocious behaviour is second nature to him. But to someone watching from home? It's like he's going to rule the heavyweight division.
"It's a passion they both love, it's what they know. Tyson has been fighting since he was 13. Jones' dad pushed him to be a great.
"It's all they know. They haven't got to compete with the young lions of the division. We're bigger, stronger, science has improved so we have more technology.
"If Tyson wants to come back and fight someone from his era, for the love of the sport? Crack on.
"I hope it adds value to the sport we love."
Joshua will defend his IBF, WBA and WBO heavyweight titles against Kubrat Pulev next and has agreed financial terms to meet WBC champion Tyson Fury in 2021.
Joshua said: "What have you seen from Fury? A couple of feints? Moving around? What have you seen that makes him seem so intimidating? Speed?
"If the sport is lacking so much talent then all you need is feints and movement to be classed as a great of this generation...
"With hard work, motivation and studying you can overcome that.
"So what do people see in Fury that is so fearsome, intimidating, that he can't be touched at the top level?
"I take him as a serious challenger, of course. But resume? It's taken him a long time to grow.
"His fight with Wladimir Klitschko was his first real challenge and he overcame it, but it took him eight years to build his experience and confidence.
"Then he had two years out and fought Deontay Wilder.
"He hasn't been in the deep end for long enough to show me that he can swim there for a long time. You have to continually prove that you belong there. You don't just come there once or twice.
"For me as a fighter, that's how you gain my respect."
Joshua was spotted wearing a leg brace and requiring a crutch recently.
"The knee is as good as it can be," Joshua told Sky Sports. "I am in full training. I didn't stop training even when I had the knee [injury].
"I'm sure many of my social media followers saw me on the heavy bag sitting down. I'm standing up now.
"I'm on two feet and I'm sure we can start sparring, so I'll be looking for some sparring partners in about a week or two to start training camp."