Question: Does a women’s gym enter into the prohibition [ie. of entering the public bath]?
Answer: These women’s gyms are a new fitnah, which the women of this time have been tested by. It is upon the women and the young girls to avoid entering into the likes of these things”
[Taken from Sharh Sunan Ibnul- Majah no. 267]
Faisal ibn Abdul Qaadir ibn Hassan