Cruiserweight champ Adamek right at home in heavyweight division

He would like to tell you that he has long pined for the opportunity to face one of the Klitschko brothers. Because he has. Really. Like most in boxing, Adamek

He would like to tell you that he has long pined for the opportunity to face one of the Klitschko brothers. Because he has. Really. Like most in boxing, Adamek has watched Vitali and Wladimir Klitschko rise to a virtually untouchable status in the heavyweight division and has longed for the opportunity to knock them off their pedestal.

He would like to tell you all those things. But the simple truth is that Adamek, the reigning IBF cruiserweight champion, is campaigning at heavyweight because his body won't let him fight anywhere else.

As a cruiserweight, Adamek was without peer. With superior hand speed and uncanny power, Adamek quickly rose to the top of the division after moving up from light heavyweight in 2007. His fights were both entertaining and decisive. In 2008, Adamek floored then-IBF champ Steve Cunningham three times on his way to winning the title. Less than three months later, Adamek destroyed undefeated Jonathan Banks, rocking him Trevor Berbick-style in the eighth round.

But even as Adamek was winning in the ring, he was fighting a losing battle with his body outside of it. Adamek would slump in his locker after each fight, his depleted body ravaged from the weight being unnaturally drained from him. Doctors had warned him of this. They presented Adamek with blood tests that showed his body was not functioning at full capacity. They warned that every pound he lost getting down to the 200-pound cruiserweight limit would make him less efficient as a boxer

So Adamek made a choice. He was a cruiserweight no more.

It wasn't an easy decision. Adamek had been chasing Bernard Hopkins for more than a year only to have Hopkins lowball him with insulting offers. He knew that a move to heavyweight would likely eliminate any possibility of a fight with Hopkins in the future. But he also knew he couldn't put his body through anymore.

"I was dropping 10, sometimes 20 pounds before fights the last few years," Adamek said in a telephone interview. "It was unnatural. I just couldn't do it."

Last October, Adamek made his heavyweight debut against countryman and former title challenger Andrew Golota. Expectations were low. Golota had three inches and more than 40 pounds on Adamek. Before the fight, Golota promised to introduce Adamek's chin to a real heavyweight punch. But in front of 20,000 fans and a television audience of 10 million, Adamek dismantled his bigger opponent, carving Golota's face with surgical jabs and sending him reeling with thudding combinations before the referee stopped the bout in the middle of the fifth round. In the locker room after the fight, Adamek walked up to his promoter, Kathy Duva, and told her, "No more fights at cruiserweight."

"When you are fighting guys that are 260 [pounds], you come to the ring with a different [mind-set]," Adamek said. "With my speed and the number of punches I throw per round, I knew I would be successful. That's the thing -- guys are bigger in this division, but you don't have to put them down with one punch."

And cruiserweight?

"No," Adamek said. "No amount of money will bring me back."

Duva, who shepherded the career of the last cruiserweight-to-heavyweight star, Evander Holyfield, believes Adamek, who will take on former U.S. Olympian Jason Estrada at the Prudential Center in Newark, N.J., on Saturday, will be enormously successful at his new weight class.

"If you look at the great heavyweights in history, a lot of them weighed the same as Tomasz," Duva told SI.com. "Rocky Marciano, Jack Dempsey, Muhammad Ali -- they were all between 200 and 215 pounds. Tomasz looks so much stronger at this weight. His legs are like tree trunks, and if you can believe it, he's lighter and quicker on his feet."

Any discussion about the heavyweight division has to include the Klitschkos, and Duva says she has been offered fights against both brothers. But, wisely, she says she will give Adamek time to acclimate himself to his new division before putting him in that position. Should he beat Estrada, Duva has already accepted a deal for Adamek to face Chris Arreola.

Adamek, for his part, is eager for a shot at a world title.

"I'm a very tough guy from Poland," Adamek said. "I know how hard heavyweights hit. I'm not afraid. I'm never afraid. I know my experience and I trust myself."