I’m guessing that you’re having a hard time figuring this out, because many places are eliminating management positions in group exercise. The big box gym I used to work for eliminated 2 levels of group-ex management a few years back, so we had one coordinator for a dozen clubs and she reported up to national.
Bravo to your club for having a full time position at this level with benefits!
Can you task out the jobs and determine the value of the position? When I was in a different type of management (tax accounting), we had to level our compensation for various finance department tasks, and we had to break down every job by what it did, how many other departments relied on it, visibility within the company and the public, etc.
Or you could set it at 30% – 40% less than the coordinator position.