Le'Veon Bell is channeling his inner Rocky in preparation for his next fight ... getting in an insane ab workout this week that looked more like torture than a typical sweat sesh.
The former NFL superstar is boxing YouTuber JMX in April ... and he's clearly taking it seriously, 'cause check out footage of the work he got in at the gym on Wednesday -- it's intense.
The ex-running back -- who quit football in 2022 to focus on his boxing career -- laid on the ground shirtless ... while one of his training partners heaved a weighted ball right at his stomach.