Joe Mazzulla has always looked like the calm guy in the room. The type of person who would politely explain a basketball play while everyone else is yelling. But apparently, there is another version of the Boston Celtics coach hiding somewhere and he knows how to throw punches.
Mazzulla recently went viral after footage surfaced of him training in an octagon. The video, shared by combat sports journalist Ariel Helwani, showed the Celtics coach working on his boxing skills and attacking the pads with serious intensity.
Joe Mazzulla is absolutely jacked. Woah.
(via @arielhelwani) pic.twitter.com/GgsHfpU3Ly
— Legion Hoops (@LegionHoops) July 14, 2026
And NBA fans were confused, because this is Joe Mazzulla we are talking about. The same guy who usually stands on the sidelines looking like he is solving a complicated math problem while his team plays. Nobody expected him to suddenly look like he was preparing for a championship fight.
It's pretty remarkable that an NBA head coach is going out of his way to find MMA gyms to train at while on the road during the season:
"I think it just keeps you fresh, mentally and physically, so that when I'm helping the team, I have a little bit of that fighter mentality. It… pic.twitter.com/QhDZmK1h8e
— Ariel Helwani (@arielhelwani) July 14, 2026
But there he was, gloves on, throwing punches and moving around the octagon like he had a secret fighting career nobody knew about.
Speaking with Yahoo Sports’ Ariel Helwani, Mazzulla discussed going to MMA gyms across almost every city the Celtics travel to during the season. It keep him sharp and helps his approach in leading a team.
“It’s the fighter’s mind. I think I have a lot of respect for the fighter, and when we’re in other cities, it’s us against the city. It’s us against not just that team, but the arena, that city,” Mazzulla said via Bleacher Report.
“I think it just keeps you fresh, mentally and physically, so that when I’m helping the team, I have that little fighter mentality. It just helps grow a little bit of an edge, and every little bit helps. And it’s fun, I enjoy it.”
Mazzulla has never been afraid of doing things differently. His coaching style has often been described as unique, and his interest in fighting sports is another example of his unusual approach to preparation and discipline.
For him, MMA training may simply be another way to stay focused, improve his mindset, and challenge himself.
