A melody of yells and grunts bounces off the walls inside Northwest High Intensity Training Center. They come from students of Brazilian Jiu Jitsu, kickboxing, CrossFit, and women’s self-defenses classes—and from their instructors, many of whom fight professionally when they're not teaching. Parents in classes can drop their children off at the on-site day care, or enroll their offspring in special kids' classes that develop teamwork and self-respect. Clients also receive diet and nutritional counseling to amplify the workouts' effects. The center’s pro shop outfits them with all the necessary gear, such as rash guards, fight shorts, and backup fists.