The men and women barreled down the steps and into the darkened room.
They were ready to fight.
Trainer Chris Nissley of Knockout Fitness in Federal Hill cued up the song “2 phones” by Kevin Gates. As the hip-hop beat pumped from the speakers, the people in the class began their attack. They pounded boxing bags with a fury of upper cuts, jabs, hooks and other punches. Neon-colored laser and LED lights bounced off the walls, floors and ceilings as they worked up a sweat.
Nissley and brother Jason, both trainers and co-founders of Knockout Fitness, have reinvented the boxing workout at their studio. They have created what they hope is a unique atmosphere that will rev...