Although the fight between Elon Musk and Mark Zuckerberg is not yet confirmed, photos of the billionaires’ training partners show that the preparation is serious.

The images include fighters and trainers who are legends in jiu-jitsu and MMA (mixed martial arts).

Check out some of the sparring partners caught training with Mark Zuckerberg below:

• Israel Adesanyatwo-time UFC middleweight champion;
• Five-time world jiu-jitsu champion Mikey Musumeci;

And those who appeared with Elon Musk:

Nigerian Israel Adesanya is a two-time UFC middleweight champion and in April this year he picked up the main victory of his career when knocks out his biggest rival, Alex Poatanwho had already beaten him three times (twice in kickboxing and once in MMA).

Adesanya has a record of 24 MMA wins (16 KOs) and just two losses. He is known for his genius hitting skills and his ability to attack with punches, kicks and knees.

Black belt Mikey Musumeci is one of the representatives of jiu-jitsu in the United States. In a sport still dominated by Brazilians, he is a five-time world champion and was the first American to win the sport’s most important title more than once.

Musumeci could have even more world titles, but he stopped prioritizing the championships of the highest jiu-jitsu federation, the IBJJF, to be an athlete of the “ONE Championship” fighting company.

The Canadian had a 15-year career as a professional, with 26 wins and only two losses, during which time he was one of the most dominant champions in welterweight history (77.1 kg) at the UFC.

American John Danaher was not successful as a jiu-jitsu fighter, but he became a trainer who is considered a genius today by the sport’s greatest fighters.

Danaher rose to fame after his team, called “Danaher’s Death Squad”, dominated major no-gi jiu-jitsu championships.

He also helped train MMA jiu-jitsu legends such as George St-Pierre and Matt Serra.

Compare Mark Zuckerberg and Elon Musk