Revenue at U.S. commercial health clubs reached $21.4 billion and memberships totaled 51.4 million in 2011, the International Health, Racquet and Sportsclub Association (IHRSA) reported in a survey released Monday. The revenue represented a 5 percent increase from $20.3 billion in 2010 while membership numbers grew 2.4 percent from 2010 when membership was 50.2 million. The total number of commercial health clubs remained flat, increasing from 29,890 to 29,960.

The total number of U.S. health club consumers, which includes members and nonmembers who visit a commercial club, grew from 58 million in 2010 to 59 million in 2011. The number of nonmember consumers remained consistent at 7.8 million. Overall, roughly 20.8 percent of Americans ages 6 and older were health club consumers. For-profit club membership penetration (members who are 6 and older) reached an all-time high of 18.1 percent.

“The health club industry continues to attract new members and is engaging them with innovative programs that are driving up frequency of club visits,” Jay Ablondi, IHRSA’s executive vice president of global products, said in a release. “Operationally, the industry is doing a better job at balancing new member acquisition with member retention and customer service.”

Member usage increased from 97.5 days in 2010 to 102.5 days in 2011, an all-time high. Increased usage often denotes member engagement, Ablondi said. Non-dues spending and increased usage are the key drivers in revenue growth as frequent usage is typically associated with increased spending in ancillary services.

“More Americans are making exercise part of their weekly routines, which is encouraging since research clearly demonstrates that regular physical activity has numerous health benefits,” Ablondi said.