Influencer Bradley Martyn Sued by Man Claiming Security Bashed Head Into Pole

Bradley Martyn -- the famous fitness influencer known for starting ZOO Culture -- is being sued by a man who says Martyn's security got rough with him ... slamming his head into a pole for no reason.

Charles Mancusco says he attended an event at the popular Encino gym back in January for the gym's 2-year-anniversary ... an event he says was open to the public.

During the event, Mancusco says he thinks Martyn and others at ZOO Culture created a frenzy by distributing free promotional materials ... while also encouraging people in attendance to use drugs and wrestle.

At some point during the night, Mancusco says he and a group of others followed Martyn out of the gym ... but, when he tried to come back in, he says he was stopped by the event's security. He alleges Martyn told the security to kick him off the premises.

Mancusco claims the security followed Martyn's direction ... beating him up and smacking his head against a large pole at the gym -- causing him to lose consciousness and sustain traumatic injuries.

He's suing Martyn for negligence, negligent hiring and premises liability. He's seeking unspecified damages.

Martyn has more than 4 million followers on Instagram, where he posts a plethora of fitness content. He's also got 3.5 million followers on TikTok ... so, the dude's a pretty big deal as far as fitness influencers go.

Logan Paul fought Bradley in an off-camera bout over the summer at his gym, BTW ... with those in attendance saying Logan won the fight.