The biggest fight in Manny Pacquiao’s career is less than four weeks away, and PacMan is working tirelessly towards getting a victory. As he prepares to take on Floyd Mayweather at the MGM Grand Garden Arena on May 2, the boxer looks as good as ever, according to his trainer.

"He is in top condition,” Freddie Roach told “Manny is a freak. He runs, and his condition...we don't have to worry about that. He'll never lose a fight because he's too tired. It just doesn't happen. It's impossible.”

Pacquiao’s physical condition has never been an issue. Even as he gets older, the boxer continues to impress. Since losing both of his bouts in 2012, Pacquaio has won all three of his fights by unanimous decision. Each fight went the distance, and in his most recent bout against Chris Algieri, Pacquiao appeared to get even stronger in the late rounds.

But could Pacquiao’s work ethic and drive to win somehow work against him? Roach has had such concerns in the past.

"He makes my job easy, you know. You don't have to motivate Pacquiao," Roach said in 2008 before Pacquiao defeated Juan Manuel Marquez. "But the thing is, right now I'm having trouble holding him back. I'm worried he might over-train."

Roach had a similar thought when the fight with Mayweather was finally agreed upon. The bout has been more than five years in the making, and Pacquiao is determined to hand the undefeated boxer the first loss of his career.

“Manny called me right away and wanted to begin training,” Roach said, via The Wall Street Journal. “But I told him to just condition for another week. Six weeks of sparring is just right. Eight weeks is too much. A professional does not over-train.”

Roach admitted to over-training Pacquiao after the third bout with Marquez. While Pacquiao won with a majority decision, it was very close with some suggesting that Pacquiao labored in the final rounds. 

Making sure he trains properly will be important for Pacquiao. He had his first professional fight 20 years ago, and ensuring that he’ll be able to go 12 rounds against Mayweather is imperative. Even if Pacquiao is able to pull off the upset, Mayweather’s defensive prowess will make him very difficult to knock out. The Filipino star has also been dealing with a calf issue that has bothered him at different points in his career.

In general, it’s not easy for an athlete to over-train. Pacquiao has fought as a welterweight for his last eight bouts, and he won’t have to worry about cutting weight to fight at a new weight class. It’s been speculated that Oscar De La Hoya over-trained in his attempt to cut weight when he lost to Pacquiao in 2008, fighting at 147 pounds for the first time in seven years.

Despite the optimism that both Roach and Top Rank CEO Bob Arum share, Pacquiao remains a +170 underdog against Mayweather.