My fellow personal trainers, we’re in an amazing business. A business that allows us to help people, and each other, become amazing.

Yet each day brings temptations to be not-so-amazing. It’s easy to be led astray by opportunities to make money we’re not entitled to, to take advantage of our proximity to attractive people we shouldn’t pursue, to cut corners, to present others’ ideas as our own, or to provide substandard service for personal gain.

We’ve all heard stories, rumors, or rumblings about fitness pros who gave in to these temptations. Trust me, it’s nearly impossible for a personal trainer to recover from a destroyed reputation. The fitness industry has a long institutional memory.

We need a code. We need guidelines to keep our industry moving forward in positive ways, and to have successful careers with our ethics intact. And you know what? Maybe we need them to be set in stone.

So here they are: The Ten Commandments of Personal Training. Like the biblical commandments, it’s easy to get confused about the order, and different faith traditions have different ideas about the fine print.

But there’s no mistaking the big-picture message about personal and professional ethics.

READ ALSO: How to Make Money in the Fitness Industry by Avoiding Eight Common Mistakes

1. Thou shalt have no other before your client

When you’re with your client, there is no one else. Don’t watch the TV in the background, don’t mess with your phone, don’t yak it up with your peers. Your client is paying you for a lot of reasons: to teach, motivate, hold them accountable, be an ally, and most important, guide them through their workouts.

Don’t worry about filling the air with “good job” and “you’ve got this” between rep counts. Be quiet and watch your client move. Apply specific cues like “knees out” or “chest up” when they need reminding. Your client can’t replicate the trainer-guided workout experience on their own. No matter what app they download, what service they subscribe to, or what research they do in their underwear, they’ll never replace your coaching.

But the best trainers do more than coach. They also know when to stop talking and listen. That’s when they learn what their clients really want.

READ ALSO: How to Make Sure You Aren’t One of the Bad Trainers Ruining Our Profession

2. Thou shalt not make any graven image

If you have to look up “graven image,” I’ll save you the time: an object of worship.

For trainers, it comes down to this: Don’t adhere to a one-size-fits-all approach when you have a diverse group of clients. You may think a certain modality is amazing and infallible, and you may even have evidence it works. But individual clients require individualized guidance.

And no matter how certain you are, there’s always more to learn. Education is one of the most exhilarating and exhausting things in human existence. It’s simultaneously exciting to learn and humbling to realize how much you still don’t know. An expert in one discipline is still a novice in countless others.

You have a responsibility to your clients, the industry, and yourself to keep learning and improving. Whether you study training methodologies, business and marketing, or the hidden history of Westeros, the more you learn, the greater capacity you have for future learning.

READ ALSO: How to Have a Long Career as a Personal Trainer

3. Thou shalt not take the names of your client in vain

Clients are an exciting and frustrating bunch. On one hand they’re the reason you get paid to do what you do. They’re also the reason you so frequently want to scream and rend your garments. Because, well, they’re people.

No matter how infuriating your clients may be in their worst moments, you can’t stop caring about them or their goals. Don’t let a client’s bad attitude or poor effort change your attitude or effort.

You’re paid to care, no matter how tough it gets.

READ ALSO: How to Tell a Client to Cut the Crap

4. Remember the seventh day and keep it as a day of rest

It doesn’t have to be Sunday, but you do need to take at least one day a week away from the gym, your clients, and maybe even your laptop.

It's harder than it sounds. We train clients because we love training. The gym is our natural habitat. Some of us even fear that if we take a day off, we’ll lose our motivation. But the truth is the opposite: If we don’t temper our motivation now, we’ll pay for it later.

You’ve told clients about the importance of recovery. Make sure you take your own advice.

5. Honor thy elders

It’s safe to guess that few personal trainers get into it with the goal of training people two or three times their age. But if you’re good at what you do and pleasant to be around, you’ll inevitably attract older clients. After all, they have both the motivation to get fit and the means to pay for your services.

So far, so good. You like helping people reach their goals, and you love getting paid.

But there’s a steep learning curve when you’re training seniors for the first time. For one thing, it takes some work just to figure out what they really want from you. When a grandmother of three says she wants to “feel younger,” or a 62-year-old former marine wants to “get back at it,” what they most likely want is to …

• Increase or maintain their mobility and physical freedom
• Prevent creeping frailty
• Prevent injury and potential falls
• Prevent or manage chronic medical conditions

They may not share these specific goals with you, or even know how to articulate them. That’s why it’s up to you to figure it out. It takes empathy and respect. But most of all, it takes your full attention. You have to hear what they say and notice what they leave out. You have to observe how they move when they know you’re watching and when they think you aren’t.

READ ALSO: What Are the Rules for Training Older Clients?

6. Thou shalt not put your clients in danger

This should go without saying. But as God is my witness, I’ve seen trainers do things that could’ve caused serious injuries, and possibly death. Like the time a trainer had his client do a jumping barbell back squat from a Bosu ball to a box.

Keeping clients safe is the most basic duty of our profession—a duty that goes far beyond avoiding the organ-donor stunts that end up in YouTube fail videos. It means understanding when a progression might be dangerous, and when a regression is the path to progress. Your clients don’t need to deadlift from the floor, back squat with a barbell, or do Olympic lifts.

What they do need is training that’s appropriate for their current goals, skills, limitations, and fitness level. Train the client you have, not your vision of what that client could become.

When in doubt, think like a doctor: First, do no harm.

READ ALSO: Give Your Clients What They Want and What They Need

7. Thou shalt not commit adultery on the job

Sexually inappropriate behavior may be the original sin of the fitness industry. Personal trainers have made unwanted advances toward their peers and clients for as long as our profession has existed. And from time to time, our clients have made unwanted advances toward us.

We’re now in the long-overdue age of zero tolerance, with clear standards for what trainers can and can’t do, and what we should or shouldn’t tolerate from others.

But we shouldn’t stop with the rules in our employee handbooks. Take, for example, the time I saw a condom fall out of a trainer’s pocket while he was working with a client.

It doesn’t matter that the majority of clients might think it was funny, if they thought anything at all. There’s still a minority who’d be offended, or even threatened. Who needs to carry a condom in his pocket at work? It doesn’t take much imagination to see what that implies.

Even if it didn’t violate the letter of the law, it was still disrespectful to both the client and the trainer’s coworkers. And that’s unacceptable.

READ ALSO: A Fitness Pro’s Guide to Sexual Harassment

8. Thou shalt not steal

While sexual harassment is our original sin, theft comes in a close second. Too many trainers think it’s okay to sell “customized” workouts online while giving everyone the same program. Or take credit for other people’s work. Or double down by taking another trainer’s workouts and selling them as a custom program. (Seriously, I saw someone do this with Eric Cressey’s High Performance Handbook.)

And how many have no problem with marketing overpriced, ineffective products because the commissions are so high? Or shortchanging clients by starting late, finishing early, and sleepwalking through half-assed programs?

These things may not meet the biblical or statutory definition of theft. But if your business model is based on delivering less than you promised, you’re stealing.

READ ALSO: Stop Lying About Your Accomplishments

9. Thou shalt not bear false witness

Your peers are not your enemies. As Jonathan Goodman once wrote about this business, “If you think you’re competing, you’ve already lost.”

In the big picture of modern life, we’re like the Spartans at Thermopylae, fighting for health and wellness against overwhelming odds. If we don’t stand together, we’ll surely fail on our own.

Don’t undercut your peers. Refuse to talk behind their backs. Actively seek out opportunities to learn and grow from your fellow trainers. And don’t be afraid to challenge someone when they violate this commandment.

10. Thou shalt not covet thy neighbor’s success

Success leaves clues, as the saying goes. But it also leaves something else: envy. It’s far too easy to become motivated by jealousy and greed instead of the desire to become the best version of yourself.

Don’t do things because you want people to see you and applaud you. Do them because everyone in your orbit—from clients to peers to followers on Instagram—needs someone to help them achieve their goals.

That’s how you build your reputation and legacy. You’ll be pleasantly surprised when you see how far it takes you.