For a young junior middleweight prospect like Jermell Charlo, sparring with top 154-pound contender Erislandy Lara is like a constant refresher course in the intricacies of technical boxing. Charlo and the southpaw from Cuba have sparred countless rounds under the watchful eye of their common trainer, Ronnie Shields, at the Plex Boxing Gym in Houston, with each session rubbing a new lesson into the rising prospect.

Yet, as Charlo (20-0, 10 knockouts) prepares for a distinctly different style of opponent in the form of lanky former 140-pound contender Demetrius Hopkins (33-2-1, 13 KOs) this Saturday, Charlo has been squaring off in the gym with a more familiar pugilist.

Jermell’s twin brother Jermall, who is the elder by a minute, has served as his chief sparring partner for this fight, which will take place underneath the Marcos Maidana-Josesito Lopez welterweight bout at the Home Depot Center in Carson, Calif. It was the first time the two 23-year-olds had sparred in nearly four years, and it’s something their trainer tries to avoid at all costs.

“I hate to do it sometimes but I was in a situation where I had to,” said Shields, a former world title challenger during the ’80s who has known the twins since they were eight. “Before, I had a problem with the sparring but I think they’re more mature now so now they know how to work with each other.”

Jermell, too, wasn’t a big fan of volleying punches at his twin, but found the experience to be beneficial.

“Sparring my brother was really tough,” said Jermell. “He’s a tall fighter (Jermall is listed an inch taller at 6’0″). I had to make the fight with him and put the pressure on him but still realize ‘Oh, that’s my brother.’ There are times when it gets tough in there, it gets real, the fight becomes serious. It was all love pushing each other to the limits.”

The twins were born in Lafayette, La., but were raised in Houston’s Third Ward. Jermell grew up wanting to be a pastor, but instead followed his father into the boxing gym, registering an amateur record of 56-8 before turning pro in 2007. Jermell is now under contract with Golden Boy, who will promote Saturday’s fight, while Jermall (14-0, 10 KOs) is with super-manager Al Haymon.

2012 was a breakout year for Jermell with three wins, including an impressive fifth-round stoppage of prospect Denis Douglin that was televised by Showtime Extreme. In his most recent bout this past January, Charlo knocked out Harry Joe Yorgey in eight rounds.

Hopkins, who is the nephew of living legend Bernard Hopkins, represents the most experienced opponent Jermell has yet faced, but the 32-year-old has spent the majority of his career at junior welterweight, where he lost a split decision to Kendall Holt for the WBO title. His career has also been marred by inactivity, with each of his two losses followed by long layoffs and weight gains.

“He’s a tough fighter, he has a very technical style,” said Charlo, who notes that Hopkins is also known to bend a rule or two. “I do know that he does move a lot and I also move a lot. What’s going to make the fight more exciting is the anticipation of what could possibly happen knowing that I hit pretty hard.

“I’m preparing for anything rough. I’m preparing for anything inside. I do know whatever he does, I’m going to keep my composure and my style.”

Shields sees the crafty Hopkins as presenting challenges for his fighter in terms of making the bout exciting, and in turn raising his stock in front of the Showtime cameras.

“If you look at Demetrius’ style, he’s just a laid back kinda guy and he likes to surprise you with punches,” said Shields. “He’s not really a come-forward kind of guy, he’s more of a boxer. But he’s slick and you have to pay close attention to what he’s doing.

“When I’ve studied Demetrius, I’ve seen a lot of things that I think are going to work with him, but the most important thing is that you can’t let Demetrius dictate anything because that’s when he gets his confidence and makes a harder fight.”

Both Jermell Charlo and Shields feel they are a few fights away from challenging the upper tier of the junior middleweight division, which includes Saul “Canelo” Alvarez, Austin Trout and Miguel Cotto. Then the training wheels can come off for good. “I feel that after two or three more fights he can challenge anybody, it doesn’t matter who it is,” said Shields. “His confidence is already there right now, which I think is the most important thing.”

Photos: Jeff Gross-Golden Boy Promotions/Gettyimages; Al Bello-Gettyimages

Ryan Songalia is a member of the Boxing Writers Association of America (BWAA) and contributes to The Ring magazine and GMA News. He can be reached at [email protected]. An archive of his work can be found at www.ryansongalia.com. Follow him on Twitter: @RyanSongalia.