This was Monday morning at Carini's House of Iron, where the proprietor, Joe Carini, does not accept feedback from one of his prized pupils, even though he is a former All-Pro running back.
"We've always had an understanding that I'm not really interested in what he has to say," Carini said.
And so it went for an hour, Barber displaying equal or greater strength than he did in 2006, the last time he played in the NFL.
There was nothing glamorous about it -- not the work or the setting, a small, no-frills gym he shared with other Carini regulars about 20 miles from the Meadowlands.
When it was over, it was time to ask the obvious: Why? What motivates a man to do this to himself at 36, four years and a series of professional and personal setbacks removed from his finest moments?
Barber ticked off his top three motivations:
"No. 1 is I need to be successful," he said. "I have that desire to do something I can control and to be successful at that I know I'm very good at. No. 2, it is doing something I love and re-finding that passion inside me that kind of fizzled out over the past three or four years.
"And it's a job. People can get cynical and say, 'You need the money.' It's not that I need the money. It's nice to have a job, something that gainfully employs you, gives you a chance to advance in your life."
(His agent, Mark Lepselter, said Barber still has "multiple seven figures in the bank" but that as he navigates a costly divorce and support for four young children, "he also needs to have an income.")
So there you have it: Another jock who could not stay away, in this case after a stretch in which his media career did not live up to its hype and the breakup of his marriage became tabloid fodder.
But there also is this: Barber's fall from public grace has been so spectacular that the only way to reverse it might be changing the subject.
Barber said that was not a motivation for him, but Lepselter knows it is Public Relations 101 and told him as much March 4, the night before he returned to Carini's gym.
"I said to him, 'Go finish the script on your Hall of Fame-caliber career and rewrite the script that has been your life for the past four years,' " Lepselter said.
Those years have been marked by a level of enmity aimed at the team's all-time leading rusher by many Giants fans that would have been difficult to imagine five years ago -- first for perceived disloyalty to his former team, then for perceived disloyalty to his wife.
Re-making his legacy
The reaction has saddened and "baffled" him at times. "I didn't get along with everybody, but I was never really mean to anybody," he said.
Soon, at last, the story will be about football, but it won't be told in New York. "There's a professional relationship there that might not work out so well," Barber said, referring to coach Tom Coughlin, with whom he clashed.
There has been speculation that the Steelers are Barber's most likely destination, with the Buccaneers -- for whom his twin brother, Ronde, plays -- also a possibility.
Barber said he regained his old strength more quickly than he expected. He isn't worried about speed, but he won't know until he gets onto a field whether his football instincts have dulled.
In March, he weighed about 190 pounds. "I used to break his chops, like, 'Man, what were you doing, spinning classes?' " Carini said. Now he is back near his old playing weight, checking in Monday at 205.
Even if Barber succeeds, he will have no more than a handful of productive years left. After that, he will try to find a better fit for a media career or perhaps tap his business contacts to reinvent himself again.
Someday, he might even get introduced at a Giants game and not get booed.
"I hope history judges me well, and I think looking back to what I was as a player, I don't know how it can judge me poorly," he said. "But if it does and fans want to hate me forever, that's their opinion.
"That's New York. You live here, you play here, you love here, you hate here. It is what it is. It's New York."