Some rivalries never die. Such is the case for Michael Phelps and Milorad Cavic, the two fastest 100 butterfliers in history. Now both retired from competition, Phelps and Cavic have remained involved in the swimming industry in their own ways. Phelps, one of the leaders of a coalition of athletes championing clean sports and anti-doping, has increased his efforts to promote honest competition now that he has more time out of the pool.

Cavic, who has taken multiple jabs at Phelps over the years, rekindled the bitterness the two have had since the 2008 Beijing Olympics where Phelps defeated Cavic in the 100 butterfly by a narrow 1/100th of a second to claim his seventh gold medal of the eight he would ultimately win in Beijing. Phelps’s self-described rant (below) was in response to a comment left on his video rather than a direct response to Milorad Cavic‘s comments last week.

“I think that comment is so rude and so beyond anything that’s really imaginable. You want to go and look at any results I’ve ever had in a drug test, go ahead.” Phelps continued: “I think it’s a joke where sports are. I think it’s unfair that there are so many athletes that are using performance-enhancing drugs. If you look at over 1,900 athletes the year before the Olympics in Rio, were not tested one time. Six months leading up to the Games I was tested 13 times just by USADA. So, you know, I think that’s something that is sad about sports today. And if you think I cheated, that’s your own opinion. I know what I did in the sport. I know the hard work I put in. And I know what went into my body, and drugs were not one of those things.”

Phelps voiced his opinion on doping in sports in general. Without calling out specific athletes or sports, Phelps said:

“People who test positive in sports don’t deserve another chance to perform because they’re doing something that other people are doing with training. I know I busted my tail for years on end, in training, trying to get myself stronger and ready for every race. And that’s what I did. I had goals, and I achieved them because I worked hard to accomplish them. There are other people that are taking the easy, cheap way out, and they’re taking performance-enhancing drugs. That’s a joke. Sports in this world today, in my opinion, some of them are great, but some of them are also a joke because there are so, so many people that are trying to find a way to cheat and get away with it. And it takes away from sports. It takes away from the true meaning of what sport is. And that’s sad. And for me, as a father now, watching my son grow up and watching him to get in sports or grab a ball, do this, do that, I think that’s something that I hope changes in years to come, so my son never has to go through some of the things that I went through as an athlete.”

Later, apologizing for his “rant” on clean sports, Phelps said:

“Sorry I went on that rant, guys, but this is something that’s such a passion for me that has to change. It’s so frustrating when people sit there and say you cheated, or you do it this way or you do that. You don’t know. I’m the only one that knows. And all the other thousands of drug tests and vials of blood and cups of urine that I’ve had to give, open-handed.”

Phelps pulled his name from the drug testing pool in November, the last step in his “official” retirement from swimming.

In response to Phelps’s testimony before House Energy & Commerce Committee on Tuesday, February 28th, Cavic voiced doubts about Phelps’s commitment to anti-doping via Twitter:

“Dear Michael,

Doping has been a problem and it’s only getting worse. I, too, don’t know what to tell my son, nor would I wish that my son ever be half as good as I was knowing what he’ll face tomorrow. People get tested, some more than others… I could even recall Lance Armstrong getting tested 3x in one day and never failed once, but that’s not the problem. At the moment, we’re not able to detect new drugs and advanced methods of doping. Why you’re seeking reform now that you’re retired, and never before supported blood passports, is beyond us all, perhaps even convenient. I’m not suggesting you’re a cheat, you’ve gradually improved your times throughout your career, but your recovery rate is nothing short of science fiction… We all just wished we could understand it. Anyway, I really do hope that you’ll stick with this, because incase our sons go pro some day, I’d like to think you made a difference #NeverTooLate”

On the eve of the 100 butterfly final in Beijing, Cavic provided Phelps with just the right motivation by saying that “It would be good for the sport if [Phelps] lost.”

Phelps’s video is posted below or can be viewed here. If you are only interested in Phelps’s statements on doping, go to the 11:30 mark of the video:

Posted by Michael Phelps on Friday, March 10, 2017

The post was not solely about doping in sports, as Phelps also answered fan questions about swimming the English Channel–he’s never going to; his favorite Eminem song–he can’t name one; and Boomer’s mobility–he isn’t walking… yet.

A previous version of this article said that Phelps’ comments were in response to Cavic, which he has clarified.

Update: Cavic, in spite of not specifically being the subject of Phelps’ response, still took to Twitter on Friday in response to Phelps’ video.

“We can keep beating around the bush, but we’re doing a disservice to the sports community for dodging powerful Q’s and taking no action,” Cavic Tweeted. “A lot of negative noise out there coming from people that neither understand the ABC’s of the drug testing process nor know the basic differences + benefits of proteins & carbohydrates. What use are words in the war against cheaters if today’s stars are reluctant to “put their money where their mouth is?” Awfully quiet out there, right now. In 2009, I regularly published my full blood results every quarter on my website. How’s that for transparency? Only one athlete out there joined the Blood Passsport movement, and he happens to be Russian – Evgeny Korotyshkin, no one else. As for you Phelps “Beliebers” out there, I’m not disputing his greatness, I just asked a question – Why now? More free time? It would have taken a quick, one-time statement of support and a small pinch for a blood sample between playing XBOX and online poker.”