Free Weights vs. Machines: Which is Better for Gains?

Depending on what gym you go to, you might have been shamed by a few bros for using machines at one point or another.

If you’re a guy, the size of your muscles is probably congruent with the amount of grief you’re given. That’s because some people see free weights and barbells as the only way to train. 

So then why do you still see people of all sizes and experience lining up for machines? Are they wasting their time? 

Let’s talk about it. 

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How Are Free Weights And Machines Different?

To start out very simple, let’s talk about what a machine is. A machine is one of those devices you see in a gym that typically has the name of the exercise, a diagram of the muscles it works, how to operate the device, and a stack of weights you can adjust the heaviness of with the use of a pin. 

One of the major benefits of a weight machine is that it takes most of the guesswork out of whether or not you have the right form to execute the exercise properly. This is because machines are designed to lock your body into a particular range of motion, so all you have to think about is lifting the weight. 

This is in stark contrast to free weights, which require a good amount of knowledge to execute the exercise properly. If you’re using dumbbells or barbells, you need to know which muscles to isolate and which direction to move in to target the muscle you’re trying to work. 

A good comparison between the two modalities is a leg press versus a squat. If you think about it, a leg press is essentially the same movement as a squat, except that you’re sitting/laying rather than standing. 

That said, for those who want to work their glutes and quads, a leg press may seem less intimidating than a squat since all you have to do is adjust the seat and weight, then push those little feets until your legs are burnt. 

WIth a squat, you need to carry a barbell on your back, which alone can be scary for some, especially if they are new to weightlifting. 

Along with that, you need to worry about the depth of your squat as well as your form. This means making sure your knees aren’t going over your toes, that your upper body isn’t leaning too far forward, your core is engaged, and that your back isn’t arched so you aren’t compensating with your lower back. 

Pretty much all of these principles are eliminated with using a machine like a leg press or a smith machine for essentially the same movement. 

So, then why to some seasoned weightlifters still hiss and sneer at the idea of using machines to work out?

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Which is More Effective: Machines or Free Weights?

I have to say from the start, I think that gatekeeping workout modalities is pretty stinking dumb. 

Like, we’re all on our own fitness journey and even if you find yourself inside a gym, that’s a win in my book, because you’ve put yourself in an environment where you’re trying to improve your health. So, anyone who tries to shame you for that is just a loser, quite frankly.

In any case, let’s talk about the effectiveness of free weights vs. machines. In general, free weights have been shown to recruit more muscle fibers, which usually translates into more substantial muscle gains. 

This makes sense because, going back to our squat example, the act of standing alone requires you to engage your core to stabilize the bar through the squat movement. It may also recruit more of the muscles in your lower body since they have to support both the bar and your body weight. 

This type of resistance isn’t always present when you have a machine doing the stabilizing of the weight for you. Indeed, one study showed that you get nearly 50% more muscle activation doing a squat with a free weight barbell than on a machine. 

Now with that said, if you’re someone who is focusing on one muscle group, like your quads for example, using a leg extension machine is going to probably do better at helping you meet that goal than a barbell squat. 

Another drawback of machines is that brands can vary wildly. The weights and range of motion on a Cybex hamstring machine can be totally different than the specs on a Star Trec machine despite the exercise name being the same. 

So, if you become overly reliant on machines to track your progress, but you travel often or need to change gyms, you could find yourself in a tough spot. 

However, free weights are exactly the weight they are labeled as no matter where you go (unless you go overseas where they use kilograms which in that case, don’t try to accidentally deadlift 500 pounds like I did once).

So, as long as you know how to maintain proper form, this can make you a much more malleable weightlifter. 

In this vein, free weights also give you more flexibility with your programming. If some jerk is scrolling tiktok on the shoulder press machine for far too long, you can easily go and pick up a barbell or some free weights and execute the exact same movement so you can be on your way.

You can also theoretically perform an entire shoulder workout with nothing but dumbbells, while reliance on machines requires you to rotate to complete a full workout of exercises.

When you go to a gym that's consistently crowded or you have a short window to squeeze your workout in, such as during lunch breaks, you may find this frustrating and it can seriously impact your motivation to stay consistent. 

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So, Why Use Machines At All?

Okay, I know I’m not making a great case for machines, but hear me out now. 

Some machines just make certain exercises more comfortable. One of my favorite exercises is the hip thrust for glutes, but being a girl without a lot of fat mass to cushion an 80 pound barbell on my pelvis doesn’t incentivize me to do it often. 

However, when I use a machine that’s heavily padded, I can safely lift more weight and not be in, like, terrible pain. The ability to lift more weight using a machine rather than a barbell can obviously translate into better strength and muscle gains. 

Machines are also great for people who are just getting started with weightlifting and want to build their baseline strength and confidence before they can be ready to mingle into the jungle that can be the weight room floor. 

If you don’t have a trainer or other knowledge on how to maintain proper form or prevent compensation or injury using free weights, machines are arguably recommended. 

They can give you a good feel of the movement to start out with, help you build more confidence with the activity of weightlifting in general, and, as silly as this sounds, just help you feel empowered to be in the gym doing…anything. In the long run, that alone goes a long way. 

Finally, machines can be useful for people with injuries who probably can’t do compound exercises. If you have a back problem and can’t do deadlifts for hamstrings, then a leg curl machine could be much safer to help you maintain strength while you recover. 

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The Bottom Line?

I usually try to stay middle of the road on most things. As a dietitian, balance is our mantra, right?

But I’m also a woman of science, ya’ll. 

When going for overall muscle gain, it’s pretty clear that free weights are superior in effectiveness to machines overall. And it makes common sense, since your body has to recruit more muscles to support your body weight when it’s not sitting, kneeling, or laying down like you would be on most machines. 

That said, though, machines are preferable in other cases. If you are brand spankin new to resistance training, want to focus on isolation rather than compound exercises, have certain injuries, or can actually lift heavier during certain exercises on a machine, then they make more sense. 

My advice would be to compose your programming of mostly dumbbells and barbells, with the option of sprinkling in some machines for certain exercises. Most effective exercise programs incorporate both isolation and compound exercises, anyway, so if you choose to use machines for the former, then you’re likely making the safe and smart choice. 

If you want to get started with resistance training yourself, but don’t know where to begin, check out my 7-Day training programs that can be started today, whether you’re trying to lean out or bulk up.