Sand-volleyball courts. Indoor pools. Cycling studios. At Fitness Works Athletic Clubs' four area locations, kids and adults alike caper about a dumbfounding landscape of fitness frills. The instructors lead a wide variety of Les Mills and Zumba group classes designed to work every muscle group. Exercisers can improve their lung capacity during BodyAttack or hone their flexibility during BodyFlow, which draws from yoga, tai chi, and Pilates. Although amenities vary by location, they all include cardio and strength-training equipment, steam and sauna rooms equipped with aromatherapy add-ons, and indoor heated saltwater pools relatively free of saltwater sharks. While adults burn calories, kids can mingle in the Kid Zone, engaging in arts and crafts or educational and fitness activities.