Smith Machine Shrugs

What the Smith machine shrug actually trains

A Smith machine shrug is a trapezius isolation exercise performed on a bar that runs on fixed vertical rails, elevating the shoulders towards the ears from a full hang.

The upper trapezius produces the movement, the levator scapulae assists with scapular elevation, and the forearms hold the bar. The rhomboids and middle trapezius contribute a little by keeping the shoulder blades from drifting forward.

The Smith machine gets argued about endlessly, and shrugs are the one exercise where the fixed vertical path is close to a perfect match. The upper trapezius elevates the scapula in an almost vertical line, so a rail that only allows vertical travel is not fighting the movement at all, which is not something you can say about a Smith machine row or squat.

Saeterbakken and colleagues compared body positions and loading modalities and found more stable conditions allow greater load while less stable ones increase the demand on stabilisers. On a shrug there is almost nothing to stabilise, so you give up very little and gain an easy setup and an easy heavy load.

That does not make shrugging more important than it is.

The range of scapular elevation is a few centimetres, and most people spend it badly. Pallares and colleagues found full range training beat partial range work, which is worth applying where there is so little range to spend. A held shrug at a moderate weight beats several bounced ones under a bar you cannot actually move.

And trap size mostly comes from elsewhere. Heavy rowing, deadlifting, rack pulls and loaded carries put the upper trapezius under long, heavy load. Shrugs supplement that.

Setting up and executing

Set the Smith bar to roughly mid thigh height, so your arms are straight when you take it.

Stand close enough that the bar hangs just in front of your thighs without dragging against them. Because the bar cannot move horizontally, this positioning is the whole setup.

Take an overhand grip a little wider than your hips, and use straps if the load is meaningful.

Rotate the bar out of its hooks and stand tall with the ribs down and the abs braced. Let the shoulders hang down fully so the trapezius starts long.

Shrug the shoulders straight up towards your ears and pause for a beat at the top.

Lower slowly over two to three seconds back to a complete hang, and start the next rep without bouncing.

The mistakes that cost you the most

Far too much weight is the fault that defines shrugging everywhere, and the Smith machine makes it easier because racking the bar is trivial. A bar that moves two centimetres is not training your trapezius. Load for a full, visible, held shrug.

Skipping the pause costs you most of the stimulus. On a range this short, the time at full elevation is a large fraction of the work the muscle does in a set.

Bouncing at the bottom removes the hardest part of an already brief range. Come to a complete hang, then shrug from a standstill.

Standing in the wrong place is the Smith specific fault. Too far back and the bar drags up your thighs; too far forward and you hold it away from your body all set.

And using the legs converts the shrug into a small jump. Keep the knees still and let the shoulders do the entire movement.

Sets, reps and rest by goal

Moderate to high reps with a controlled tempo.

For muscle gain, three sets of ten to fifteen with ninety seconds rest. For strength, four sets of six to ten with two minutes, though there is rarely a reason to chase shrug strength as an end in itself. In a fat loss phase, three sets of fifteen to twenty with a minute.

Tempo is the variable that matters. Two to three seconds down, a full hang at the bottom, and a genuine pause at the top. Roig and colleagues found eccentric training produced greater strength gains than concentric work, and the lowering phase on a shrug is the part almost everyone throws away.

The machine makes drop sets easy, since you can rack the bar at any height and strip a plate without setting anything down.

Straps on every working set. Grip is not the target.

Schoenfeld and colleagues found a dose response between weekly hard sets and hypertrophy, but count honestly: heavy rows, deadlifts and carries already load your traps, so two or three shrug sets a week is usually the right addition rather than six.

Refalo and colleagues found stopping a rep or two short of failure produces comparable growth, and the natural stopping point here is the rep where you can no longer hold the top.

Where it fits in your split

At the end of a pull, back or shoulder session.

On push, pull and legs it goes at the end of pull day. On a bro split it closes back or shoulder day. On an upper and lower split it finishes the upper session. On a full body programme it is optional and easy to cut.

The specific reason to pick the Smith version over a free barbell is that you can load it heavily, rack it instantly and train alone with no setup beyond walking into the machine. For a movement where the setup is often more annoying than the exercise, that is a real advantage.

The reason to be honest about it is that this, the free barbell shrug, the dumbbell shrug and the behind-the-back version are essentially the same exercise. They differ in where the load sits and how easy the setup is, not in what the upper trapezius does.

So choose on comfort and convenience, and spend the time you would have spent deliberating on a set of carries instead.

Once or twice a week alongside your normal pulling is plenty.

Variations worth knowing

The free barbell shrug lets the shoulders travel in whatever line suits them, which matters slightly more than it does on most Smith exercises, though not by much.

The dumbbell shrug puts the load at your sides with nothing to drag against your thighs, and gives the cleanest vertical line of pull available.

The behind-the-back Smith shrug moves the bar behind the hips, which keeps the shoulders from rolling forward and shortens the range further.

The trap bar shrug uses a neutral grip with the weight in line with your body, and is often the most comfortable version of the lot.

The farmer's walk trains the traps under long duration tension while building grip at the same time, and for many people it does more than any shrug.

And the rack pull loads the trapezius under very heavy partial range pulling, which is a different and often more productive stimulus.

What the evidence says

Kara and colleagues measured trapezius activation levels and the ratios between its regions during scapular retraction exercises, which supports treating the trapezius as a group with distinct portions and not assuming that shrugging alone trains all of it.

Ludewig and Reynolds reviewed scapular kinematics and their association with glenohumeral pathology, supporting attention to how the shoulder blade moves under load rather than only to how much weight is on the bar.

Saeterbakken and colleagues compared body positions and loading modalities and found stability influences both the load handled and the stabiliser demand, which is why a fixed rail costs you almost nothing on a movement with nothing to stabilise.

Pallares and colleagues found full range training outperformed partial range training, which is the central argument for using the whole few centimetres a shrug offers rather than half of them.

Roig and colleagues found eccentric training produced greater strength gains than concentric training, supporting a deliberate two to three second lowering phase.

Schoenfeld and colleagues found a dose response between weekly hard sets and muscle growth, with the honest caveat that heavy pulling already supplies a good deal of trapezius volume.

Refalo and colleagues found stopping short of failure produces comparable growth, and the practical cue on a shrug is to stop when the top position can no longer be held.

Common questions

Is the Smith machine bad for shrugs?

No, and this is the exercise it suits best. The trapezius elevates the scapula in a near vertical line, so a vertical rail is not fighting you the way it does on a row or a squat. You give up almost nothing and gain easy heavy loading.

How is this different from a normal barbell shrug?

Barely at all. The bar is on rails, so you cannot drift and the setup is faster. The muscles do the same thing through the same range. Pick whichever is free.

How much weight should I use?

Enough that you can shrug your shoulders visibly towards your ears and hold the top for a beat. The pause is a better investment than another plate.

Do shrugs build traps at all?

Yes, but they are a supplement. Heavy rows, deadlifts, rack pulls and carries load the upper trapezius under greater tension for longer. Add two or three shrug sets a week if traps are a priority.

Should I do these in front or behind my body?

In front, generally. Behind the hips keeps the shoulders from rolling forward, but the bar catches on your glutes and shortens an already short range. Use whichever lets you hold the top comfortably.