Free Weights VS Machines

There’s a long-standing debate about free weights and machines.

It goes something like this:

Person A: “Free weights are king! They challenge all of the little stabilizer muscles! Machines make you dysfunctional!”

Person B: “Free weights are too unstable and you can’t get strong using them! You need to use machines to grow big muscles!”

Both people have a point.

Yet both miss the mark.

Rather than completely prioritizing one implement over another, we should identify the trade-offs of each and ask ourselves which implements would more closely align with our goals in the gym.

This creates a more nuanced perspective, which allows for a better understanding of which implements best serve which goals.

Free Weights VS Machines - Similarities

Free weights and machines are both sources of resistance.

Both grant an ability to load our bodies to challenge muscular contraction.

And both follow the same principles of physics that every other force does.

Whether you’re picking your child up off of the ground, lifting rocks because you think it’s manly, or pressing dumbbells on a bench, force is force - no matter where you are.

Force has 3 primary qualities (there are several more that are not acutely relevant to the context of lifting weights):

1. A point of contact (location).

2. A direction (a straight line from the location).

3. A magnitude (an amount).

To identify how each implement differs, apply the above 3 qualities to each scenario.

And it doesn’t need to be more complicated than that.

Imagine the rock-lifting scenario.

You lift the wrong with your hands - point of application.

The rock wants to pull you toward the ground - direction.

The rock weighs 50 pounds - magnitude.

Now imagine you’re performing a chest press, pushing against a machine handle.

You push against the handles with your hands - point of application.

The handle wants to shove your hands back behind your body - direction.

There are 50 pounds on the weight stack of the machine - magnitude.

Fundamentally, these forces can be viewed through the same lens.

There are differences between lifting a rock (or a dumbbell) and pressing against a machine - what are they?

Free Weights VS Machines - Differences

The primary difference between free weights and machines is constraint.

What’s a constraint?

A constraint is a limitation or restriction that’s defined by context.

If I lie down on a bench to perform a dumbbell press, the bench constrains me from falling backward. The ground constrains the bench. My feet constrain my knees, hips, and spine on the bench.

When I begin to move the dumbbells, however, I can move them in any direction.

I can press them over my face.

I can press them over my chest.

I can raise them over my head.

But this constraint increases the more weight that I lift.

You know this intuitively.

You can’t dumbbell press the same amount of load (magnitude) that you can dumbbell flye.

You can’t skull-crusher the same amount of load that you can press.

So, as magnitude increases, constraint does, too.

But constraint falls along a spectrum.

The heaviest dumbbell press that I can perform constrains me to press a single way.

If I deviate from the technique into a weaker position, I no longer can perform a press with the same amount of load.

But what allows for that deviation?

The fact that the dumbbell itself is unconstrained.

Now imagine doing a machine chest press.

Regardless of the weight that you choose, you can only move the machine in a single direction.

The machine doesn’t care if you sit higher or lower in the seat.

The machine doesn’t care if you face the wrong way.

Regardless of what you do, the machine only moves one way because it’s completely constrained.

The distinction now becomes…

Should you do something that’s more or less constrained?

And herein lies the answer that can completely differ from one person to the next.

More constraint leads to more predictable, standardized reps.

Less constraint leads to less predictable, potentially distinct reps.

In general, technique is easier to standardize on machines than free weights.

But because free weights are fundamentally unconstrained, technique can be adjusted to a much greater degree.

Imagine the chest press versus the dumbbell press again.

The machine moves in a single path - and you must trace the path of your arm along with the path of the machine. If you don’t, the machine feels weird and clunky.

The dumbbell moves wherever your hand does - and assuming you’re using a challenging load, you can trace your arm path wherever you prefer, as long as your elbow and wrist align under the dumbbell.

So, when using a machine…

• Your technique is more standardized.

• Your movement options are limited.

This leads to more consistent reps and easier learning.

But it also leads to more rigid constraints that you may or may not be comfortable exercising within.

When using dumbbells…

• Your technique is less standardized.

• Your movement options are greater.

This leads to less consistent reps and higher difficulty in learning.

But it also leads to fewer constraints, which may allow you to exercise more comfortably.

Hopefully, my point here is clear…

This isn’t a question of which implement is better - that makes no sense.

Our reference for “better” or “worse” should depend on the context and goals of why we’re doing an exercise to begin with.

Does it make sense to try to load your quads with a free-weight barbell squat if you’re not built in a way that easily allows for that?

Or does it make more sense to sit down on the leg extension or hack squat?

Does it make more sense to use the shitty, 20-year-old chest press that’s half-broken when you’re rehabbing a shoulder injury?

Or does it make more sense to use dumbbells and a bench to align the resistance to what you can comfortably do?

The less black-and-white we think, the more we’re able to navigate these kinds of questions based on the context at hand, and the more we’re able to problem-solve across a variety of scenarios.

The more black-and-white you think, the fewer problems you’ll be able to solve.

One tool may be appropriate for the job on week 1, but another tool may be more appropriate on week 4 when new information about that tool emerges.

So, are free weights better? Or are machines better?

It’s a non-starter.

I hope this helps.

-Ben

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