We’ve covered the basics of gym etiquette before, and a lot of it is basic common sense. Put things back where you found them, share nicely, be polite. But I know a lot of you have more questions—maybe you’re even shying away from the gym (or some part of it, like the weight room) because you’re not sure what’s okay.
Source: LifeHacker – Ask Us Your Gym Etiquette Questions