Sixty-one 100-pound punching bags hang from chains like an upside-down fitness forest at Title Boxing Club in Naperville. On any given day, this expansive workout area finds men and women donning gloves and punching or kicking up a sweat in fitness classes built on the fundamentals of competitive boxing and kickboxing training. Group classes, also known as Power Hour sessions, are led by a team of trainers whose previous experience ranges from boxing and playing college football to earning degrees in kinesiology. These classes are complemented by private lessons that make use of the facility’s speed bags, free weights, and cardio machines. An onsite ring allows students to practice their footwork while learning how to protect the face—that is, by learning how to wear Kevlar mustaches.