But demand makes these establishments profitable.

About 15 million Chinese had gym memberships and the fitness market reached 30 billion yuan ($4.35 billion) last year, iResearch Consulting Group analyst Meng Hezi said.

"Increasing fitness awareness and technological development have enabled the sector to upgrade," Meng said.

"Most gym members are ages 20 to 40. They're middle-class urbanites who earn at least tens of thousands a month and hold high statuses. They're lured by a sense of achievement and social opportunities."

Meng predicted the market will continue to further specialize.

"Fitness' current market penetration is only 1 percent. And its demographics are diversifying. So more themed gyms will appear with increasingly tailored services."

Emergent segments will target the elderly, new mothers and people with health problems, iResearch forecast.

Competition will heat up as brands saturate major metropolises, requiring them to expand into smaller cities if they can afford to, he added.