Revealed: Why Oleksandr Usyk wears straps on his arms ahead of blockbuster Tyson Fury clash... as the Ukrainian boasts 'the hard work is done' for the heavyweight bout

Oleksandr Usyk has shared a photo of a brutal practice to help him ahead of his historic bout against Tyson Fury.

The two heavyweights will go head-to-head in a little over a week's time in Saudi Arabia in a bout that will decide the undisputed champion of the weight division.

Opinions are split on who will come out on top in the fight, with both men undefeated and proud champions but putting it all on the line in a fight that has been dubbed one of the biggest heavyweight clashes of all time.

Both men appear to be doing all they can to grab an extra edge ahead of the fight, and Usyk took to social media to reveal a common - but uncomfortable - technique to do just that.

He shared a post-training photo on his Instagram account on Thursday, with fans questioning why he had two devices wrapped around his biceps.

The devices were belt-like objects that are used to restrict blood flow to the arms, a technique boxers often use to help build muscle.

The bands are known as pneumatic restriction cuffs and the Ukrainian had no qualms about showing them off online. 

With less blood flow to the muscles, they therefore receive less oxygen and tire quicker.

Pressure around the limb also leads to pooling of blood in the limbs, which causes hypertrophy, and is only usually carried out by trained professionals.

It causes muscles to swell and get bigger, meaning the boxer is effectively stronger ahead of their fight, which is what Usyk is likely aiming for.

In the photo, captioned: 'The hard work is done,' the 37-year-old, who boasts a 21-0 record in professional boxing - including back-to-back wins over Anthony Joshua - can be seen sat on the edge of a ring post-workout.

'He no longer looks like a blown up cruiserweight,' one fan commented on the post.

Another added: 'I feel Fury will lose.'

While Usyk has been looking to put on weight ahead of the bout, Fury has displayed his slimmed-down physique ahead of the rearranged fight.

Although it has been reported that the star eats 6,000 calories a day, he stunned fans with a body transformation in a topless photo shared on his own social media.

Fury, who is defending his WBC belt against Usyk on May 18, shared the snap on the social media platform with the caption 'Undisputed incoming' and the date of their fight.