I know that PlayEnable offer an management system which offers you the tools to log all the information you require for running your gym. It can also be integrated into your own website so that you can take bookings from your site. This is where to find them http://plus.playenable.com/facility-signup/features.I hope I helped
Ben Pittsley -Voted upRay Elbe - Surprised no one has mentioned champions way?I'm currently using Championsway. They recently released a web based platform similar to mind body called "perfect mind". I went with them for compatibility issues. I have ~ 1300 memberships with them and didn't want to deal with the transfer to Mind body.
Mindbody is another one
...TTT as this is relevant to my interests
Mind body seems like a more robust system, less expensive, and better tech support.