His job is to take Shawn Thornton punches — one after another, repeatedly, for hours.

Tommy McInerney is his name, and no, he’s not out of his mind. McInerney is a boxing trainer at The Ring on Commonwealth Ave. in Allston, and he’s serving as Thornton’s sparring sensei — fine-tuning the Bruins enforcer’s biggest asset: his fighting.

“It’s a long day, but hopefully, it will pay off halfway through the season,” Thornton told Stephen Harris of the Boston Herald. “It switches up the monotony, too. It used to be I’d go for a run or whatever to get a sweat. Coming in here is a lot more fun than anything else I could do. Fighting isn’t the main reason I’m here. I mean, I know it won’t hurt me in that regard, but the reason I signed up was more the conditioning than anything. It’s such a tough workout doing this. One day, I lost seven pounds in here.”

The Hub’s brouhaha badboy has been involved in a few on-ice altercations in his day. According to hockeyfights.com, Thornton has dropped the mitts 156 times in his career — including 51 times in the NHL regular season, one time in the postseason, 19 times in the preseason and 85 times in the AHL. Thornton had a career-high 17 fights this past season to go with a career-high 11 points and 123 penalty minutes.

The left winger has been cleaning the ice with the game’s biggest bruisers since his arrival in Boston two years ago, but like every aspect in the game, there’s always room for improvement. That’s where McInerney comes in.

“He knows how to fight already,” McInerney told the Herald. “So what I do is touch up all his skills, his form. I teach him how to throw punches the correct way, so he doesn’t burn out so fast. He was throwing a lot with his shoulder, big punches. What I try to do is have him throw 10 more punches, faster and harder, because speed equals power. We get him to do a lot of mitt work — throwing lefty and righty. We spar a lot in the ring, and it’s just speed, speed, speed, turning over his hands. I think he’ll throw with a lot more power that way.”

Speed and precision to Thornton’s hammering blows? That’s bad news for Bruins opponents and great news for Thornton’s teammates.

In the 16 games in which Thornton threw down his mitts last season (he fought twice against Atlanta on Nov. 12), the Bruins went 10-6. Whether this proves that the B’s respond well to or pick up their game more when Thornton’s fists are flying, it’s going to remain the 6-foot-2, 217-pounder’s M.O.

“I’m just hoping that something like this will give me a little bit of an edge in the end,” Thornton who spent eight seasons in the AHL, told the Herald. “I’m not the most gifted hockey player, so I try to do a little bit extra on top of everything else, to try and give myself, maybe not an advantage, but just to keep up. It’s been a long road, but I’m here.”