Although revenue for Life Time Fitness increased in second quarter 2014, the company's net income decreased, and its stock plunged today after the company announced its financials.

Life Time Fitness, Chanhassen, MN, grew its second quarter revenue by 6 percent to $326.6 million from $308.1 million in second quarter 2013. For the first six months of 2014, revenue has grown 6.6 percent to $638.5 million from $598.9 million during the same period last year.

Net income for second quarter 2014 decreased by 10 percent to $29.8 million from $33.2 million in second quarter 2013. For the first six months of 2014, net income was $58.1 million compared to $61.3 million for the same period last year, a decrease of 5 percent.

"Our second quarter was challenging," Life Time founder and CEO Bahram Akradi said on a call with analysts this morning. "As we have said in the past, the health and fitness space continues to fragment at a rapid rate. That fragmentation has led to membership acquisition and retention becoming a little more challenging at some of our mature centers."

Life Time's stock was $41.26 at the end of trading today on the New York Stock Exchange, a 14 percent decrease from the day's open of $47.91.

Total memberships have grown slightly for Life Time to 823,021 on June 30, 2014, from 812,866 on June 30, 2013, a 1.2 percent increase. Attrition increased slightly in the quarter—0.1 percent—compared to last year. However, attrition for the 12-month period ending June 30, 2014, increased even more: 35.8 percent compared to 34.5 percent during the 12-month period ending June 30, 2013.

"We have a double whammy right now," Akradi told analysts during the call. "We have flat in-center revenues. We have flat dues in mature centers. And in order for us to grow again, we have to invest in dramatic measures. We're doing a good job with our current model. We have to change the model a little bit."

Life Time Fitness lowered its revenue expectations to $1.29 billion to $1.31 billion from $1.3 billion to $1.32 billion. Net income expectations were lowered to $120 million to $125 million from $125 million to $130 million.

In the second quarter, Life Time opened new clubs in Des Moines, Iowa, and Bloomfield Township, MI, outside of Detroit, bringing the company's total to five new clubs so far this year. Life Time will open one more club this year in the Las Vegas market during the fourth quarter.

Akradi announced that Life Time will open six new centers in 2015, including new markets in the Boston area and Sacramento, CA. Other markets include Toronto, New Jersey and Long Island, NY, Akradi said.

Life Time also announced a share repurchase program under which the company may repurchase up to $200 million of its outstanding common stock through June 2016.

Akradi made one more announcement: Eric Buss, who had been serving as interim CFO, is now the permanent CFO at Life Time, effective July 21.