Every type of club has its own customs, like the secret code word that Howard Cunningham used to get into the Leopard Lodge on Happy Days. Health clubs don't have secret code words, of course, but you may feel more at home if you know a few of the unwritten rules. Here are some tips on how to act in certain situations:

• If someone's using the weight machine that you want, ask whether you can work in. That's a term for alternating sets with another person. Asking to work in is perfectly legitimate; no one has the right to camp out at one weight machine for a half-hour.

Working in with someone is convenient if all you have to do is switch the pin in the weight stack. But it's awkward if you have to readjust the seat or add or subtract weight plates. In those cases, waiting until the person is done is a better choice.

• If someone is standing over your shoulder waiting to use the machine that you're on, kindly ask that person to work in with you. Or tell the person how much longer you plan to use the machine. Say something like, "This is my last set. Then it's all yours."
• If you need help adjusting a machine or you forget how to use it, turn to a staffer or a gym member with a kind face and say, "I'm new here. Can you help me?"
• If someone's doing an exercise that you want to learn, find an appropriate break in that person's workout and ask him or her to show you the exercise. Most people are happy to help -- in fact, they'll probably be flattered that you asked.
• If you aren't 100 percent sure that you can safely complete your repetitions, ask someone to spot you.
• If someone's hitting on you and the feeling isn't mutual, close the conversation with a pleasant, "Have a good workout," and then move on to your next weight bench or machine -- preferably on the other side of the gym.