Ms. Merlucci Reno, a former Golden Gloves champion, was known as the Manhattan Mauler during her amateur career; she turned pro in 2013.

Ms. Merlucci Reno stands 5 feet tall, which is short even for her weight class — junior flyweight, or 108 pounds — and it is quite a sight to see her give pointers as she squares off against some of the larger members of the team.

Ms. Merlucci Reno said she grew up in the small town of Hackettstown, N.J., as an “arts nerd” and moved to Brooklyn when she was 18 to study at Pratt Institute. But eventually she ran short on money and switched to part-time acting classes and bartending.

At a friend’s suggestion, she began taking kickboxing classes and eventually agreed to compete.

Ms. Merlucci Reno began working out in kickboxing gyms, where she met Mr. Reno. She said they were friends and training buddies for several years before becoming a couple. Both then switched to boxing exclusively. Ms. Merlucci Reno became a nationally ranked amateur and in 2007 won the New York Daily News Golden Gloves.

She and Mr. Reno live in the Kips Bay section of Manhattan and train amateur and professional fighters together, in addition to coaching the Bravest squad. Aspects of their “gym buddy” relationship remain, she said, including her habit of referring to her husband by his last name.

“It’s just out of habit,” she said, “from being in the gym together, and cheering for his fights.”

In 2008, Ms. Merlucci Reno competed in the Battle of the Badges as an honorary firefighter. She won and upstaged her husband, who also fought that evening.

“I won by a knockout,” Mr. Reno recalled, “and all anyone talked about was my wife’s match.”

She taped up the hands of Matthew Restrepo, 23, a firefighter and a welterweight from Brooklyn, and then turned to Josiah Rivera, 30, a 180-pound firefighter who was punching a double-end bag tethered by elastic lines to both the ceiling and the floor.