Founded in 1983, 24 Hour Fitness USA Inc. is one of the largest fitness club chains in the United States, serving over 4 million members in more than 420 clubs. The center provides personal training services, group exercise classes and a selection of strength, cardio and functional training equipment. Located in Bellevue, Wash., it has partnership with consumer brands, including Coca-Cola, Dial, Everlast and Nike. 24 Hour Fitness USA Inc. is a part of Forstmann Little & Co., an equity firm.