Oleksandr Usyk claims he's considering moving back to cruiserweight following his Dec. 21 rematch with Tyson Fury. Should that occur, the marketeers will tell you he’s attempting to set new records, enhance his legacy and create yet more history.

Yet history dictates that such a move would be unwise, particularly when one considers he will turn 38 years old in January.

Usyk left the cruiserweights behind in November 2018 after a comprehensive clear-out. His final action as a 200-pounder was to defeat Britain’s Tony Bellew in a defense of his undisputed crown. When knocking out the Liverpudlian in eight rounds, Usyk weighed a shade over 198 pounds.

Since then, across six bouts at heavyweight, Ukraine's Usyk has weighed between 215 and 223½ pounds. He reached the heaviest point on that scale for his May 18 victory over Tyson Fury, a superfight in which Usyk claimed his fourth sanctioning body title to gain recognition as undisputed champion in a second division.

One suspects he will enter the sequel with Fury at a similar weight.

“When I start to prepare for my training camp, I have to eat all the time [at heavyweight], Usyk told "3 Knockdown Rule" podcast. “For me, it’s hard. I don’t like it.”

“I think maybe after the [Fury] rematch I am going to go down in weight to cruiserweight.

“I want more cruiserweight. Maybe I can be undisputed for a second time in the cruiserweight division. It’s my plan.”

Maybe Usyk will do that. Maybe it is indeed his plan. Or maybe he’ll think better of it.

Fighters who drop down the divisions late in their career rarely find the descent to their liking once they get there. Though the weight loss might be aesthetically healthy, what follows once inside the ring is far from it.

The consequence of Roy Jones Jr.’s excursion to heavyweight is surely the most famous case in point. In September 2002, the 174-pound Jones looked typically unbeatable when he defended his collection of light heavyweight titles with a sixth-round thrashing of Clinton Woods. Six months later, after hitting the scales at 193 pounds, he decisioned WBA heavyweight belt holder John Ruiz while retaining all his magic. 

In his next bout, in November 2003, he shed 18 pounds and eked past Antonio Tarver over 12 rounds. It was widely regarded as the flattest performance of Jones' career to that point.

In May 2004, at 35 years old, Jones was knocked out in two rounds by Tarver in their rematch. He was never the same again. He would blame the strain of gaining muscle and then losing it as the reason behind his alarming slump in form.

Chris Byrd, a former heavyweight belt holder, decided to ditch some poundage after a 2007 loss to Alexander Povetkin. For that 11th-round defeat to the Russian, Byrd –  a mere middleweight at amateur level – weighed just over 211 pounds.

Eight months later, after losing more than 30 pounds, he entered the light heavyweight division insisting he felt born again at the age of 37. He had originally planned to only drop down one division, but after running seven miles a day and eating smaller portions, he claimed he still felt fat. So further down he went.

“I’ve lost the weight; now I have to see how I’m going to adapt to fighting at a lower weight,” Byrd said at the time. “I can spar and train, but until I get in there and compete I won’t know if I can compete in this weight class.”

Byrd could barely stand up, let alone compete. Live on ESPN, in May 2008, Byrd was taken apart by Shaun George in nine rounds. The final knockdown caused the dislocation of his shoulder, and he was rushed to hospital after the fight.

In December that year, Oscar De La Hoya returned to welterweight for the first time in seven and a half years, at the age of 35. Manny Pacquiao battered the corroded shell of De La Hoya to such an extent that he was rescued on his stool after eight rounds.

There are exceptions, of course. In 2018, Nonito Donaire turned his back on the featherweight class to be reunited with his old 118-pound frame for another run at bantamweight, a division he had ruled and then abandoned seven years previously. At the age of 35, Donaire won another world belt and then, at 38, he claimed another in the same division.

Donaire, however, lost eight pounds.

For Usyk to rule again at cruiserweight, after five years of honing his body for the challenge of fighting the giants of boxing, he’ll need to shift more than 20.