Koncrete Gym, Phoenix

A visit to Camelback Boxing Gym means lacing up your gloves and bracing yourself for an intense workout. Boxing, MMA, and kickboxing dominate the group fitness schedule here, although gym-goers can also pair off with personal trainers for one-on-one workouts that are customized, meaning they use monogrammed kettlebells. Instructors and trainers on the Camelback team have trained Olympic boxers, won national and international championships, and landed punches that aired on HBO.