

Luke Rockhold doesn't come right out and use the word "cheater" when referring to his opponent on May 18.





But the final Strikeforce middleweight champion doesn't really need to. As far as Rockhold is concerned, Vitor Belfort's build simply doesn't pass the eye test.

"Just look at his physique," Rockhold said in a recent one-on-one interview with Yahoo! Sports. "Look at how he looks at [36 years old]. You can't tell me that at his age, something like that looks natural."

Belfort is one of a handful of fighters in their 30s and beyond – along with the likes of Chael Sonnen and Dan Henderson – who experienced career resurgences after undergoing testosterone replacement therapy (TRT), a controversial-but-legal treatment.

Rockhold, though, isn't buying it.

"TRT use is something I don't agree with at all," Rockhold said. "It's a way to get around the system. They say TRT is needed for low testosterone, that it's a medical condition. Well, what causes low testosterone? Prolonged steroid use is one cause."

[Related: Vitor Belfort defends TRT usage]

Belfort was suspended by Nevada for nine months in 2006 after testing positive for the banned substance 4-Hydroxytestosterone after a loss to Henderson in a Las Vegas PRIDE card.

"It's frustrating to someone like me, who's fought clean, has no reason to cheat, and has done things the right way," Rockhold said.

The TRT talk has created a charged atmosphere for Rockhold's first UFC fight, which is the main event of UFC on FX 8 in Jaragua do Sul, Brazil. For his part, Belfort, a Rio native, hasn't taken one step backward from Rockhold's assertions.

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On Monday, he told MMAFighting.com he considers Rockhold's words disrespectful. "I don't know what he did in the sport," Belfort (22-10) said. "I think it's disrespectful, the way that he thinks. "But it is what it is. You cannot control it, you cannot control people."

A product of The American Kickboxing Academy in San Jose, Calif., the MMA home of Cain Velasquez, Daniel Cormier, Josh Thomson, and Jon Fitch, Rockhold first made waves in the sport by recording his first seven career victories via first-round finish.

But then the 28-year old Santa Cruz native had to sit through a couple periods of prolonged inactivity. First, there was a 17-month span in 2010-11 in which a shoulder injury kept him out of action. Then, after winning the Strikeforce middleweight title, he's only fought once in another 17-month stretch, as he, along with the rest of the company roster, watched from the sidelines as the company died a slow, painful death.

"Success in this sport's so much about momentum," Rockhold (11-1) said. "It's tough sitting out on the sidelines like that. That's when I most appreciate being a part of a gym like AKA, where you've got someone like Cain, who's dealt with a major injury, someone like Daniel who's been through the ups and downs… coaches who have been there and done that."

[Also: Anderson Silva fined $50K for skipping media event]

As if the war of words over TRT weren't didn't already add intrigue, Rockhold admits to carrying a bit of a chip on his shoulder on behalf of his former company. Former Strikeforce fighters like Cormier and Thomson have made successful UFC transitions in 2013. Even those who have come up short, as former Strikeforce lightweight champion Gilbert Melendez did in a split decision against UFC champ Ben Henderson, have acquitted themselves well in defeat.

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