The long-serving Reds defender played the last of his 737 games for the club when they beat Queens Park Rangers 1-0 on the final day of last season, and Carragher has said that he has taken up a new sport since taking his boots off.
"I'm not training to become a boxer by any means, but it is interesting to see how they stand, how they hit, I'm asking them the tiniest little details to try and improve," Carragher told the Daily Mail.
"When I finished playing I thought to myself 'I have got to keep fit'. I didn't fancy running on the treadmill in the local gym. I knew a few of the lads here and I had been in briefly in the past before pre-season.
"I come in here and we will argue about boxing; we will argue about Liverpool and Everton. It could be the game that was on last night, people giving me stick over something that I have said on TV or written in the paper. But it is brilliant. I come in and we have a good blast."
Carragher has been training alongside Liverpudlian boxer Tony Bellew at a local gym in the city.