24 Hour Fitness is the world's largest (by memberships) privately owned and operated fitness

Physical fitness

Physical fitness comprises two related concepts: general fitness , and specific fitness...

 center chain, and third in number of clubs behind Gold's Gym

Gold's Gym

Gold's Gym International, Inc. is an international chain of co-ed fitness centers originally started in California by Joe Gold. Each gym features a wide array of exercise equipment, group exercise classes and personal trainers to assist clients...

 and Fitness First

Fitness First

Fitness First is the largest privately owned health club group in the world with over 540 Fitness First clubs worldwide reaching over 1.7 million members in 21 countries...

 of the UK. It currently has 425 clubs and over 20,000 employees in the U.S.A. The company has its corporate office located in San Ramon, California

San Ramon, California

-2010 census:The 2010 United States Census reported that San Ramon had a population of 72,148. The population density was 3,991.1 people per square mile...

 and a processing center located in Carlsbad, California

Carlsbad, California

-2010:The 2010 United States Census reported that Carlsbad had a population of 105,328. The population density was 2,693.1 people per square mile . The racial makeup of Carlsbad was 87,205 White, 1,379 African American, 514 Native American, 7,460 Asian, 198 Pacific Islander, 4,189 from other...

. The founder is Mark S. Mastrov and current CEO is Carl Liebert III.