The Smith machine is a polarizing piece of exercise equipment. Some people absolutely love it—it’s one of the most popular pieces of equipment in most gyms.

But walk into a strength and conditioning facility, and there’s little-to-no chance you’ll find a Smith machine. The general consensus among strength coaches is that it’s a waste of money and space.

Ben Boudro, a strength coach who owns Xcleration Sports (Auburn Hills, Michigan) falls into this category. “The Smith machine is such a waste of space. It takes up room in my gym and offers very little bang for the buck,” he says.

We have to agree. When it comes down to it, there’s no reason to do exercises on a Smith machine if there are free-weight alternatives. Here’s why.

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It Changes Your Exercise Technique

Free weights like dumbbells and barbells allow you to move freely—hence the name. Nothing restricts your natural movement when you perform an exercise.

Smith machines are designed to restrict your movement. The bar can only move vertically on the slides since it’s locked in place horizontally. So you can only perform exercises that require a pure vertical push.

If you’re accustomed to free weight exercises, doing the same move on the Smith Machine will likely feel awkward, because it forces you to conform to a perfectly vertical bar path. And this can cause some problems.

When you do the Bench Press correctly, the bar actually moves in a slight J-curve path. This maximizes the amount of weight you can press and protects your shoulders. On the Smith Machine, you can only press the bar straight up from the starting position, which is typically just below the line of your nipples.This limits the amount of weight you can press, because the bar is further away from your shoulders.

The difference in the Squat is even more drastic. To properly execute a Smith machine Squat, you must step forward so you’re almost leaning back against the bar. Ideally, this is done on a Smith machine with a slightly angled bar path. The resulting squat position looks almost like you’re sitting in a chair.

Some view this as safer because there’s little stress on the back—although this shouldn’t be an issue if you squat correctly. Problem is, the Smith machine Squat takes your glutes and hamstrings out of the movement, which leads to the next problem.

It Can Cause Joint Problems

Turning off your glutes and hamstrings during a Squat puts a ton of stress on your knees. They should not be primarily responsible for handling the weight. Your hips should be doing the majority of the work.

But the problems don’t stop there. If your anatomy doesn’t perfectly match up with the fixed bar width, it might pull your joints out of their optimal range of motion. Freedom of movement is always preferable to forcing your joints into a set position on any exercise.

You might not hurt yourself in a single workout, but you need to consider the long-term ramifications. As an athlete, you should be primarily  concerned with staying healthy and injury-free. Your sport probably beats up your body, so you should limit unnecessary stress in the weight room as much as possible.

“When you use a Smith machine, you do the same movement pattern over and over again, and it’s often in a poor position,” says Boudro. “That’s not always good for your joints, and you may eventually overuse them, causing serious damage to your joints.”

That’s not to say people don’t experience joint issues on free weight exercises, especially if their technique is poor. But the Smith machine is problematic, because it forces you into what we view as mistakes that add stress to your body.

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It Turns Off Important Core and Stabilizer Muscles

The purpose of the Smith machine is to make exercises easier. That’s why a whole plane of motion is eliminated. You don’t need to focus on controlling the bar, which makes for a more stable movement.

However, on the Smith machine, you don’t engage critical core muscles and stabilizer muscles, which are meant to protect your joints and spine, and keep your body in control. A 2005 study found that core and trunk muscle activity was superior in the free weight Squat compared to the Smith machine Squat.

“It allows you to turn off your stabilizing muscles, which is good for nothing. In sports and in everyday life, there are very few instances where we lift a fixed amount of weight in one plane of motion,” says Boudro. “Whether it’s lifting a box down from the garage or defending a block in football, we always have to be able to fire our stabilizers and move our bodies in multiple planes of motion. The Smith machine can’t help you with that.”

Bodybuilders might argue that the Smith machine helps them increase the challenge to specific muscle groups for this reason, because stabilizers are out of the picture. And that’s fine for them. But athletes need those stabilizers. It’s non-negotiable.

It’s Not as Effective

Put simply, Smith machine exercises are not as effective as their barbell counterparts. A 2009 study found that average muscle activation was 43 percent greater on the barbell Squat.

So not only do Smith machine exercises put you in a poor position, you’re missing out on serious strength benefits if this is your preferred piece of equipment.

It’s Not as Safe as It Looks

The Smith machine is supposed to be a safe alternative to free weights. But don’t let it fool you. You can still fail a rep, just like with a barbell, and it’s impossible to dump the weight. Yes, you can hook it on the pins, but of course it’s possible to miss.

But most important, the form alterations and stress on your joints simply aren’t worth it. The No. 1 goal of training when you’re an athlete is to never get hurt in the weight room. Smith machines don’t fit with this priority.

The Smith machine can be used for Inverted Rows, Inclined Push-Ups and some butt-building exercises—but that makes it a very expensive towel rack. Some of you probably love the Smith Machine for your main lifts, but we encourage you to change your loyalties. Stick to classic barbell exercises and other free weight moves for better results and safer workouts.