One and done: Michael Phelps calls for a lifetime ban for anyone who's caught doping

“If you test positive, you should never be allowed to come back and compete again, cut and dry,” Phelps said. “I believe one and done.”

The World Anti-Doping Agency and World Aquatics have acknowledged that 23 Chinese swimmers tested positive for a banned substance ahead of the Tokyo Olympics. The results were not made public until media reports surfaced this year, with both bodies accepting the Chinese explanation that the positive tests were caused by tainted food.

Nine of those swimmers won medals - several as part of relay teams - in Paris, leading British star Adam Peaty to gripe that the playing field was not even.

Phelps reiterated those sentiments, saying the Chinese swimmers who tested positive should not have been allowed to compete in either Tokyo or Paris.

Or anywhere else, for that matter.

“If everybody is not going through that same testing, I have a serious problem because it means the level of sport is not fair and it’s not even,” he said. “If you’re taking that risk, then you don’t belong in here."

Extra testing

When Phelps was setting multiple world records and becoming the most decorated Olympian ever, he knew there were plenty of people who scrutinized his performances, who wondered if he could be pulling off such amazing feats without a pharmaceutical boost.

Phelps said he actually subjected himself to extra testing in the leadup to the 2008 Beijing Olympics —where he broke Mark Spitz's iconic record with eight gold medals — to alleviate any doubts he was racing clean.

“People called me a cheater throughout my career,” he said during a wide-ranging media availability put on by one his sponsors, Omega. “I subjected myself to do more testing — blood and urine — weekly. Why? For the reason that I could say I’m not cheating and I am clean and here are the results.

"I did it the clean way,” he added. “I won 23 Olympic gold medals the clean way. It can be done.”

Phelps said he always felt like some competitors were doping during his five Olympics, in which he won 28 medals overall.

“I don’t think I ever competed in an even playing field or a clean field,” he said. "I have some speculations of some athletes that I competed against that I thought they were (doping). But that’s out of my control.”

Mental health, anti-doping

Since retiring from the sport after the 2016 Rio de Janeiro Games, Phelps became more outspoken about issues such as mental health and anti-doping efforts. He recently testified before the U.S. Congress on the latter issue, calling for major reforms to a system that many people believe is broken.

“What has to happen is everybody has to come together and figure out one way to test everybody all over the world. Period,” Phelps said. “And if you test positive, you should never be allowed to come back and compete again.”

He said he understands the frustration of athletes such as Peaty, whose British team finished fourth in the men's 4x100-meter freestyle relay Sunday — a race won by the Chinese.

“It does break my heart to see people put hard effort into four straight years to prepare for an Olympic Games, then to have it taken away from them by somebody who is cheating,” Phelps said. “It’s not right. I stand for that and I will always stand for that.”

He has a suggestion for athletes who want to dodge the rules.

“Go ahead and go to the cheater games," he said. “Keep the Olympics about integrity.”

Marchand's big moments

Phelps said he was not surprised at all by Léon Marchand's performance at his home Olympics, where he won four individual gold medals and a relay bronze.

Phelps was most impressed by Marchand winning gold in the 200 butterfly and 200 breaststroke on the same night.

“That's probably one of the greatest doubles we’ve ever seen in the sport,” Phelps said.

He chuckled when asked about Marchand being called the next Phelps.

“When I was trying to compete, I was trying to be the first to ever do it," Phelps said. “I’m sure he has that same goal.”

If Marchand wants to after the record eight gold medals at the next Summer Games in Los Angeles, Phelps will be cheering him on.

“I know how hard it is, but I also know how talented he is,” Phelps said. “I’m looking forward to seeing what he does next.”

Improving athlete experience

Phelps has heard complaints about the athletes village in Paris, and he hopes future hosts will devote more attention to the accommodations.

Italian swimmer Thomas Ceccon was spotted napping in a park to catch up on his sleep, and other high-profile athletes have lodged complains about the lack of air conditioning, poor food and cardboard beds.

Phelps said he stayed in the village during all five of his Olympics, even after becoming one of the world's most famous athletes.

“I wanted to be a part of the Olympic Games,” he said. “There’s nothing better than being in one small city where you get to see people from all over the world.”

The conditions were always a bit challenging, he remembered.

“We brought those foam egg cartons to put on top of our beds,” Phelps said. “My ankles were hanging off the bed at every single Olympic village I ever went into. We all had three or four fans in our rooms because it’s typically hot."

Moving forward, he said, “Let’s think about what the athletes need and what they need to perform.”

No chance of a comeback

The 39-year-old Phelps scoffed at speculation that he might be planning a comeback, even though he doesn't think it would be unfeasible for him to compete against today's swimmers.

The subject did come up when he was watching the U.S. Olympic trials with his son Maverick.

“My 4-year-old asked me if I could still get in the water and swim and race these guys,” Phelps recalled. “And I said, ‘If I wanted to, I believe I still could.’

"And then I said to him, ‘But you wouldn’t get to see Daddy. Daddy would be at the pool all the time. I wouldn’t take you to school. I wouldn’t pick you up from school. I wouldn’t be making you dinner. I wouldn’t be having dinner with you guys. And he said, ’I don’t want that.' And I said, ‘I don’t want to do that, either.’ So I’m not coming back.”