You can go even further. A lot of places can be kept WHITE ONLY just by requiring a membership-fee and an issued ID to enter: think Costco. Niggers don't shop there because they're not going to self-ID at the door when their intention is to shoplift, not to mention the idea of paying a membership fee now to shop later is impossible to the 15-minute niggerbrain; future-nigger is literally stealing from now-nigger.
If you want to create a gym and keep the foids out, just make it concrete no-decorations walls, cast-iron free-weights, no wifi and enough interference that data doesn't work, no music, no classes, no sauna... just iron weights and nothing else. Put up a sign at the front that says something like GRUNTING AND SWEATING ENCOURAGED, and they'll avoid it like the plague.
Just think of the things that the group you want to restrict cannot stand and they'll self-isolate.
How many "private clubs" exist that are effectively white only just on account of the fact that they have an application process and they've never found a colored person that qualified? There must be thousands of them.