Free Weights Vs Machines for Muscle Gain

A lot of people have this terrible misconception that only free weights are useful tools for building serious amounts of muscle mass.

When in reality – nutrition and rest aside – taking a muscle through its contractile range under sufficient tension is how you build muscle optimally.

It doesn’t matter whether you apply this tension using a free weight or machine.

What’s important is creating optimal tension in the target muscle to elicit the adaptive response that causes the muscle to hypertrophy (grow).

The battle between free weights and machines (…and which is better) is long fought. But today, I offer some clarity and direction in the use of these tools as part of a progressive training program.

I’ll let you into a secret – The only way to truly maximize muscle growth from your training is to optimize the use of both free weights and machines.

There’s two key considerations you need to think about when selecting exercises.

  1. Does this combination of exercises stimulate the target muscle though all points of the strength curve?
  2. Does this combination of exercises work the muscle though its full range of motion?

You need to break free from the whole meat-head mentality that “free weights are the ultimate mass builders” or “you must bench, dead, and squat to get big” – because this dogma is utter nonsense.

Don’t get me wrong.

I’m not saying that free weights are bad, or in any way inferior, or that machines are better at building muscle. They both have their place and can complement each other.

You just need to learn how to use them together, effectively.

Today, I’m going to talk about the pros and cons of free weights and resistance machines, and how to utilize them both to build more muscle.

I’ll also be talking about some studies that will show you how to combine these exercises for greater gains in muscle mass than using one alone.

Benefits of Using Free Weights

Free weights are exercises performed using primarily dumbbells and barbells – or kettlebells – or any weighted object that you can move freely and works directly against gravity.

Certain cable machines can be considered “free weights” – since the resistance is not set on a fixed path of motion – rather, it can be moved in 3-dimensional space.

Activation of Stabilizer Muscles

I’m sure you’ve heard the “stabilizer muscles” argument, and how great free weights are at developing these muscles.

But how much of an impact does this really have on overall muscle size?

Most free weight exercises require muscular balance and coordination from the whole muscle group to resist and move the weight. This unstable training environment helps to activate and develop stabilizer muscles that aren’t as well activated by machines.

However, activation of these small muscles won’t translate into more muscle mass, they simply help to support joint stability and develop “functional strength”.

The whole muscle group works synergistically to keep the joint balanced, strong, and healthy.

The main benefit here is that development of these stabilizers will improve your lifting technique and form – and that’s it.

Functional Movements

Free weight movements such as barbell squats, barbell deadlifts, overhead dumbbell press, and pull ups are considered “functional” because the movement of the exercise mimics natural movements your body makes in everyday life.

Free weights are great tools for building functional strength, speed, and power.

If you’re looking to improve your athletic ability for sport, then functional free weight exercises are the better choice for you.

Greater Range of Motion

Some people really like the freedom of movement that only free weights allow, and in some cases, free weight exercises provide a greater range of motion.

Flat dumbbell press, single arm dumbbell row, and Arnold presses are good examples of exercises where free weights work better than most machines in this regard.

They provide a fuller range of motion, and because the hands come closer together on the concentric, there’s a better contraction at the top of the movement.

Why does this matter?

Free Weights vs Machines Studies

Several good studies comparing full range of motion to partial range of motion have found the former to result in superior muscle mass gains.

That means, lifting a moderate load over a full range of motion results in more muscle growth than if you were to lift a very heavy load over a partial range of motion.

The results of the study pictured below shows that deep squatting increased greater lean muscle mass gains than a shallow squat.

| Effect of range of motion in heavy load squatting on muscle and tendon adaptations. Bloomquist K1, Langberg H, Karlsen S, Madsgaard S, Boesen M, Raastad T.

And another study:


Compared gains in biceps muscle thickness from sets of preacher curls performed with full and partial range of motion.

They found that the full ROM group increased bicep thickness by 9.52% and the partial ROM group increased bicep thickness by 7.37%. Although not as significant a difference as the first study, it again gives full ROM the edge at building muscle.

So, incorporate free weight exercises into your program to provide muscular tension over a range of motion greater than a fixed machine.

With that said, that doesn’t mean you should neglect machines, because combining a machine can create tension at different points of the strength curve – an often overlook advantage that I’ll get into later – and provides several other benefits.

Always choose range of motion over weight. Most serious injuries in the gym are caused by the misuse of excessively heavy weights.

A common problem I see with people using free weights is that they tend to go too heavy.

Likely because they’ve been falsely informed that heavy free weights are essential “mass builders” for skinny guys.

Flat dumbbell and barbell presses are a prime example.

You’ll see guys having to put extreme effort into balancing the weight – jelly arms wobbling all over the place – and forcing it from point A to point B, recruiting every muscle in the general vicinity to move the weight.

You know who you are.

This is NOT how you go about building muscle.

Sure, take advantage of the strengthening effect on stabilizer muscles, as developing strong stabilizer muscles will build better form and allow you to get stronger at that specific lift.

A couple more pros for free weights worth mentioning is that they’re the ideal choice for setting up a home gym. Dumbbells and barbells don’t take up much space and they’re relatively cheap compared to variable plate loaded machines.

Free weights burn more calories than machines, since a lot of the exercises involve more muscles to move the weight. If you’re on a fat loss program, then free weights would be a better option for you.

And finally, several studies have shown that free weight exercises increase way more testosterone than machine exercises.

Whether an exercise induced increase in testosterone results in more muscle mass is still up for debate, but it certainly won’t do any harm to have more of this anabolic hormone in circulation.

Cons of Using Free Weights

Some free weight exercises such as the barbell bench press are hard to progress on without the aid of a spotter. Pushing out those last couple of reps as you reach failure and following the principle of progressive overload requires a spotter.

Not ideal if you mostly train alone.

Most free weight exercises come with a learning curve to develop proper lifting technique.

These are just a couple of minor drawbacks that can easily be worked around.

Now, let’s talk about those machines that ego lifters love to hate on.

Benefits of Using Machines

Resistance machines are those things at the gym that you sit on. They usually have some kind of lever that you push or pull on through a fix path of motion.

The pec deck, smith machine and leg press are examples of resistance machines that work a muscle group through a fixed plane over 2-dimensional space.

First things first.

You’ve probably heard it plenty of times – “free weights are way better than machines for getting bigger and stronger”.

I fell for it, too.

But it’s just not true.

I know, it’s hard to believe, watching and listening to the “big guys” pressing those huge dumbbells.

And don’t be thinking that all the greatest bodybuilders used just free weights because you watched a few YouTube videos of Ronnie squatting 800 ‘solid ass’ pounds of iron.

Sure, they used them a lot, but machines were a big part of their training, too.

All of the best-known bodybuilders – Arnold Schwarzenegger, Frank Zane, Phil Health, Jay Cutler, Ronnie Colman, and Dorian Yates – used free weights and machines in their training programs to build championship winning physiques.

Here’s some research on the matter:

This very interesting study | The Effects of Training with Free Weights or Machines on Muscle Mass, Strength, and Testosterone and Cortisol Levels

Had this to say:

“The original hypothesis was that the free weight group would have greater increases in muscle thickness however, this was not the case. Significant and similar increases in biceps and quadriceps muscle thickness were experienced by the free weight group and machine group. There were no significant differences between machine and free-weight groups over time.

That’s right, their study found that muscle mass gains were equality good with free weights and machines.

But there’s more…

“The machine training group experienced a greater increase in machine bench press strength compared to the free weight training group.”

The study also found that the participants using machines gained more strength than the free weight group, as you can see from the graph below:

The machine bench press came out on top here because trainees didn’t have to worry about stability. They were able to focus more of their attention on isolating tension and contracting the pectoral muscles.

The machine group was able to apply more force output from the chest muscles because there was less stabilizer muscle activation.

As the evidence above shows, machines can increase direct muscle strength as effectively (or more) as free weights can.

Further, Researchers from Valdosta State University took the strength stats of two groups on the bench press.

Both groups were then placed on a 10 weeks training program, with one group using a free weight bench press and the other on a machine bench press.

After the 10 weeks both groups were assessed for strength gains on the free weight bench, comparing their strength from before the 10 weeks training program.

What they found was that BOTH groups equality increased their strength by around 10%.

Now that we’ve dispelled this long-standing myth, let’s talk more about machines.

Better Isolation of Target Muscle

Machines provide constant isolated tension to the target muscle group.

Less Involvement of Stabilizer Muscles

As I’ve mentioned, developing stabilizer muscles is great for stability. But when you’re trying to maximize the development of a specific muscle, you want the tension on that muscle, and nowhere else.

Machines don’t involve the use of many stabilizer muscles, which allows you to place the target muscle you’re trying to grow under more growth stimulating tension.

This is ideal for bringing out lagging body parts, or simply to maximally develop each muscle over your spit routine.

For example, when bench pressing using a free barbell, there’s a lot of involvement from the shoulder muscles (front and middle deltoid) and to some degree the rotator cuff.

This shifts some of the physical tension and neurological attention away from the chest muscles and is likely the main reason that the study above showed the machine exercise was slightly better than the free weight at increasing strength.

Less involvement from other muscles means that you’re able to contract and keep the target muscle that you’re trying to grow under greater isolated tension.

Now, that’s not to say you should only focus on machines, because free weight functional movements are more natural and help to keep your joints healthy.

What I’m saying is, both have their place and complement each other as part of an overall training program.

Safe and Easy to Use

Machines are a great choice if you’re training alone, without a spotter, as they are locked into a guided path with limited range of motion. You don’t need to worry about a lump of heavy metal coming crashing down on you as most have built in locking mechanisms.

There’s usually a label with clear instruction on how to use the equipment properly, and displays which muscles groups the machine works, making them a good choice for beginners.

Apart from isolating muscle groups and manipulating tension at different points of the strength curve, experienced lifters also use resistance machines for drop sets, as adding or subtracting weight is simply a matter of moving a safety pin.

It’s harder to cheat when using machines as your body is in a stable position. There’s no swinging weights around and cheating with momentum.

Cons for Machines

Machines are set to move over a fixed path that may not suit your body size.

Everyone has different body dimensions – length of limbs, torso, and muscle and joint structures. This means that not all machines are going to be a good fit for you, and if you’re training in a poor position of alignment, you’re going to end up with an injury over time.

Yes, you can adjust seat height and lever position, but that doesn’t guarantee that you’ll be training in the optimal alignment. And if there’s awkward joint resistance, you could develop a repetitive strain injury on the joint.

If your joint is resisting against poor alignment – you’re not going to bend the machine metal to make corrections – it’s the soft tissues of the joint that will take the damage.

A barbell is a barbell, pretty much.

But machines come in different forms. I prefer plate loaded leverage and hammer strength machines over those flimsy commercial cam pulley and weight stack machines.

The hammer strength machines feel solid, smoother, with consistent tension.

Covering The Tension Curve with Free Weights & Machines

Every exercise applies a certain level of tension across the muscle.

Some exercises create high levels of tension from the start of the movement, while with others, tension is greater at the end.

We all know how great bicep curls are at bulking up arms, that’s why they’re a staple in most arm training routines.

However, because dumbbells and barbells use gravity to create force, their tension range is very limited.

Let me explain…

When curling a barbell for example, gravity is the load vector, so the maximal point of tension placed on the biceps is when the forearm is perpendicular (90 degrees) with the floor.

At the halfway point of a bicep curl exercise with a barbell or dumbbell is when the muscle receives maximal stimulation. The further away you move from that halfway (90 degrees) the less work is required of the biceps and therefore less stimulation for growth.

The image below shows the differences in tension between barbell and cable.

When you start to curl a dumbbell, there is low resistance at the starting position.

As you curl the weight, the resistance increases and peaks at the halfway point.

Then, tension decreases as you reach the top of the range.

Now, when using a high cable machine, the handle is not directly working against gravity.

The tension is greater at the end of the range of motion.

As you can see, compared to the barbell, the tension is maximized at the end of the movement.

This concept might be a little hard to get your head around, so let’s explore this a bit more.

Mechanical tension within the muscle is needed to stimulate growth.

Resistance exercise (weight training) is the tool we use to create this muscular mechanical tension.

But choosing the best combination of exercises to get the most growth stimulation from your workout can be tricky.

Now, the problem is that all exercises “work” to stimulate muscle growth. Every resistance exercise – performed correctly – can stimulate protein synthesis.

Take the biceps for example, the list below shows a selection of exercises that effectively targets the biceps muscles.

  • Barbell Curl
  • Dumbbell Curl
  • Cable Curl
  • Preacher Curl
  • EZ Bar Curl
  • Concentration Curl
  • Machine Curl
  • Overhead Cable Curl
  • Hammer Curls

standing, seated, incline, decline… on and on.

All of the above exercises place the biceps under tension and will effectively stimulate the growth process. What we must do is choose a small combination from this list to create the greatest amount of growth stimulating tension to build the muscle.

And here’s where most people go wrong.

Let’s say John wants to grow his biceps.

He selects a couple of staple exercises:

  1. Barbell curls
  2. Seated dumbbell curls

Looks pretty good, right?

Sure, this combination of exercises will stimulate growth of the biceps, they’ll “get the job done”, but they’re not optimal.


Because these exercises are not creating high tension at the beginning and end of the movement.

John’s exercises are effectively the same, they create maximum force / tension in just the middle of the range.

Every exercise has something called a “tension curve”. The ‘curve’ gives a graphical representation of the muscles contracting force as it moves through an exercise’s range of motion.

Tension curves vary from exercise to exercise and generally create one or more of the following curve patterns throughout its range of motion:

  • Ascending
  • Descending
  • Bell shaped


A tension curve in which the muscular tension increases throughout the range of motion, until the end of the contraction – tension peaks at the end of the movement.


A tension curve in which the muscular tension decreases throughout the range of motion, until the end of the contraction – the tension peaks at the beginning of the movement.

Bell Shaped

A tension curve in which the muscular tension required increases then decreases – the muscular tension peaks in middle of the movement.

Dumbbell curls are a very common biceps exercise. When doing free weight dumbbell curls, the point where the dumbbell reaches the middle (half way point) of the movement is where the muscle is placed under the most stress and tension.

Therefore, the muscle will develop the greatest amount of strength in the middle of the range of motion.

When the dumbbell is resting by your sides in the starting position of a biceps curl, there’s no tension going through the biceps.

As you curl the dumbbell up, the tension increases and peaks at the middle of the movement, then becomes less at the end.

If you were to always just train biceps with exercises that maximizes tension at the middle of the range then you will become strong at this point of the tension curve, but weaker at the beginning and end of the muscles range of motion.

Adding an exercise like machine low and high cable curls will change the tension curve by creating more tension at the bottom and end of the range, where the dumbbell curls can’t.

This way, you maximize tension over the full range of motion.

With different exercises, you can create greater overall stimulation of the muscle by apply tension at all points of the strength curve.

Here’s a better combination of biceps exercises for John:

  1. Dumbbell Curls
  2. Low Cable Curls
  3. Machine Curls

This combination has the biceps muscles working through all points of the strength curve, maximizing muscle fibre recruitment.

I’d like to show you another great study that shows how sensibly using a variety of machines and free weight exercises can build better overall development of the target muscle.

| Effect of the shoulder position on the biceps brachii emg in different dumbbell curls. Liliam Fernandes de Oliveira, Thiago Torres da Matta, Daniel de Souza Alves, Marco Antonio Cavalcanti Garcia, Taian M. M. Vieira

In this study they examined biceps activation with dumbbell biceps curls and preacher curls.

What they found was that these exercises complimented each other by activating tension at different point of the strength curve.

Each of the phases at the bottom of the chart represents the angle of flexion – or the range of motion.

DBC – means dumbbell curl.

As you can see, with the free weight dumbbell, tension was greatest at the middle of the movement (phase 3).

Now, look at the results from the preacher curls. Tension was greatest at phase 1 / 2, near the start of the movement.

DPC – means dumbbell preacher curl.

So, combining a free weight dumbbell, and dumbbell or machine or cable preacher curl will help to stimulate the muscle across different points of the strength curve.

This is why free weight and machines work best together for maximizing muscle growth – all bases are covered.

Tension manipulation is best achieved by using a mix of free weights and machines.

Take the side deltoid for example. Tension can be varied across the muscle with the use of dumbbells, cables, and Machine Deltoid Raises.

Here’s another example of this at play:

Exercise Variety

You can build strength and size with free weights alone, but if you want maximum hypertrophy gains you must incorporate both machines and free weights into your training routine.

I see a lot of people in the gym moving from one piece of exercise equipment to another, in the belief that they’re effectively varying exercises, because they heard that exercise variation helps to build muscle.

But moving from flat dumbbell press, to flat machine press, to flat barbell press in the same workout is not optimal variation.

Performing smith machine shoulder press, then barbell shoulder press, then machine shoulder press isn’t, either.

These are effectively the same exercises – it’s the same movement repeated, without change to the tension curve, or to targeted portions of the muscles.

You see, muscle groups are made up of diverging, partitioned, bundles of muscle fibres, and are responsible for complex movement patterns – i.e. – angle of pull and plane of movement.

Randomly hitting the muscle with different exercises is not optimal, it takes some thought, because of the way muscles are partitioned into fibre bundles.

Free weights and machines are doing the same thing internally, – they contract muscle against load.

When working muscle groups with various exercises, try to select a few exercise that will work the muscle across different points of the strength curve.

Bottom Line

Free weights (barbells and dumbbells) are at the center of power athletes training programs. If you’re a powerlifter and training for sport then sure, free weights will work best for you.

But for bodybuilders and those looking to build muscle groups – mindfully mix machines and free weights for best results.

Last updated: 21/08/2019