At Energy FitBox, Bob is always up for a fight. He wears blaring orange t-shirts with goading slogans such as “I am your daughter’s first date” with the hopes that you will kick and punch him all the harder. So who exactly is this instigator? Bob—or B.O.B.—is a Body Opponent Bag used as each person's sparring partner during the studio's signature kickboxing classes. Small class sizes enable more individualized attention, and the hard-hitting workouts not only burn boatloads of calories and tone arms, legs, and abs, but they also help relieve stress and teach self-defense techniques. New Clark Avenue location now open.