Inside Usyk's heavyweight transformation & biggest weakness

Oleksandr Usyk’s place as a future hall of fame inductee cannot be disputed.

The 37-year-old Ukrainian is a fighter who will be heralded as a boxing great in years to come.

On Saturday, Usyk will look to further secure his legacy by becoming the first ever four-belt heavyweight champion when he takes on Briton Tyson Fury in Saudi Arabia.

“Oleksandr is a superstar,” former opponent Tony Bellew tells BBC Sport.

Usyk reigned supreme as an amateur, winning European, world and Olympic gold.

In the paid ranks, Usyk won his first cruiserweight world title in just his 10th professional bout, before travelling to fellow champions’ backyards and cleaning up the division within five fights.

“If he beats Tyson, he can go down as one of the greatest fighters ever,” says Bellew.

BBC Sport looks Usyk’s transition from the world’s best cruiserweight to a unified heavyweight champion who dethroned Anthony Joshua in 2022, before winning the rematch just months after defending his country against the Russian invasion.

After defending his undisputed cruiserweight crown against Bellew in November 2018, Usyk – with nothing left to achieve in the division – jumped to heavyweight.

Quite remarkably, the 6ft 3in Usyk had previously fought as a middleweight in the amateurs.

For all his natural talent and boxing prowess though, there were question marks over whether he had the size to compete with boxing’s big boys. Only Evander Holyfield and Briton David Haye had won world titles in both divisions.

But with a strong focus on strength and conditioning, swimming and full-body workouts, Usyk steadily built into the weight.

He took 10 months out and added just over a stone – weighing 15st 3lb - for his heavyweight debut against Chazz Witherspoon.

Despite still giving up nearly two stone, Usyk eased to a stoppage win.

He gained two more pounds for a harder-than-expected points win over British gatekeeper Derek Chisora in October 2020.

“He wanted to stand there with 'Del Boy' and see how the power was and whether he could take the punch – which he did,” Bellew says.

Witherspoon and Chisora were far from elite-level contenders but Usyk felt ready for a huge step up in opponent against champion Joshua.

Usyk – who missed the birth of his child while training for Fury earlier this year – is dedicated to his craft.

Swimming forms a key part of his training. According to his manager, Egis Klimas, Usyk swam 10km nonstop as preparation and was able to hold his breath for four minutes and 40 seconds.

Juggling and catching coins are Usyk’s staple party tricks, but they too signify the importance he places on shaping his cat-like reflexes.

The training and focus paid dividends against Joshua - Usyk’s resilience and fitness levels were on full show when he outclassed the Briton for most of the 24 rounds they shared.

Usyk came in at 15st 11lb for both fights – which he seemingly feels is his optimal weight having tipped the scales around the same mark against Daniel Dubois in August.

Joshua was 20lb heavier and then 23lb in the rematch.

“I kept saying that Joshua was just too big, but the size was matched by just how good Usyk is,” Bellew says.

Still there are those who still question Usyk’s heavyweight credentials.

Bellew describes Usyk as a "novice heavyweight in some ways" having never been pushed to his "absolute limit".

For Bellew, however, Usyk’s superiority and ability to find an extra gear is key.

“Usyk ticked all the boxes in the second AJ fight,” Bellew says. “Going into round nine or 10, he is behind or it’s level. Then going into the championship rounds, Usyk just finds another level.”

When negotiations for the Fury fight in April 2023 stalled, Usyk turned his attention to WBA mandatory challenger Dubois.

Dubois landed a body shot in the fifth round, sending Usyk to the canvas. The punch was declared a low blow.

“In my humble opinion, my guy delivered and landed the perfect blow on the beltline and he should be the one facing Tyson Fury,” Dubois’ trainer Don Charles tells BBC Sport.

Regardless of the legalities of the punch, Charles says it exposed an Usyk vulnerability.

“It was well documented prior to Daniel facing him that Usyk doesn’t like being hit to the body,” Charles says.

“He has an old injury here. There were moments in the second AJ fight where he turned around citing a low blow but it wasn’t.”

Usyk was dropped by body shots twice in the amateurs. On both occasions, Usyk rose to his feet and outpointed his opponent.

Former world champion Hannah Rankin believes Fury might be "too big" for Usyk.

“If he can target the body, it could be Usyk’s undoing,” she says.

Bellew, however, dismisses this supposed weakness as a “myth.”

“I've had my ribs broken on numerous occasions. It hurts and it's not nice, but he's not weaker than anyone else in the body,” Bellew says.

“Maybe he doesn't carry as much protection around the midriff than someone like Tyson Fury, but he takes a body shot like everyone else.”