Are Preacher Hammer Curls Worth Doing?

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Preacher hammer curls are a legitimate, wrist-friendly way to train your elbow flexors, but they are not the brachialis specialist most lifters believe they are.

The bench does something real. The grip does less than gym lore promises.

Here is what the exercise actually trains, who should keep it, and who should swap.

Table of Contents

Key Takeaways

They train the biceps brachii, brachialis and brachioradialis together, with no single muscle isolated.
Controlled electromyography (EMG) research does not show a neutral grip beating a supinated grip.
The preacher bench’s real edge is growth in the lower part of the arm.
Pick them for wrist comfort and zero body momentum.
Expect noticeably less weight than on standing hammer curls.

The Viral Argument Against Hammer Curls On A Preacher Bench

One short lifting video has talked a lot of lifters out of this exercise. The argument is sharper than most gym takes, which is why it stuck.

What The Argument Actually Says

The case is mechanical, not vibes. Flexing your shoulder forward over the pad pre-shortens the long head of the biceps and cuts its contribution, and a neutral grip is another way of reducing biceps involvement.

Stack the two and you pay twice for the same effect.

The creator’s own summary is blunt: a supinated preacher curl is ideal, a hammer preacher curl does not make sense.

The same creator rates a cable preacher curl with a swivel handle as their best lengthened-position option. So the objection is about the resistance profile, not the preacher bench.

Where The Argument Holds Up

On a free-weight preacher curl, the hardest point of the rep is the bottom. A EMG comparison of dumbbell curls found the preacher version produced the highest activation at the very start of the lift, then dropped off sharply as the elbow bent.

A 2020 training study backs this up. Strength at the near-straight elbow angle climbed 39 percent over 10 weeks of barbell preacher curls, against 30 percent for a cable version, while gains at the mid and flexed angles came out level.

So you get a brutal bottom and an easy top. If your goal is loading the forearm muscles through the entire range, a standing or cable hammer curl does that better. That half of the critique is correct.

Chart comparing where the rep is hardest on a free weight preacher curl, a standing hammer curl and a cable preacher curl

Where It Falls Apart

Then comes the finding that breaks it. Across 63 young women, eight weeks of preacher curl training grew the distal region of the elbow flexors, the lower third of the upper arm. Incline curls grew the proximal region instead.

That distal region is brachialis territory, the muscle sitting under your biceps. Preacher curls grew the exact part of the arm a hammer grip is supposed to be for.

The position also dumps load onto the short head, so it earns a slot beside your other short head bicep exercises.

No study has compared preacher hammer curls head to head against standing hammer curls for growth either. Whatever grip bias exists is min-maxing.

Preacher Hammer Curls Muscles Worked

Search this exercise and you will find pages that flatly contradict each other on what it trains. One lists a single muscle. Here is the version that matches the research.

Infographic of the three elbow flexors worked by preacher hammer curls and which biceps head the exercise biases

Biceps Brachii

The two-headed muscle on the front of your upper arm, and yes, it is still working here.

A study on 10 competitive bodybuilders found a supinated grip produced about 12 percent more biceps activation than a neutral grip on the way up, and about 19 percent more than a pronated one.

Translated into gym terms: if a bigger biceps peak is the goal, the hammer grip gives some of that activation away.

Brachialis

The flat muscle sitting underneath your biceps, and the reason arms look thick from the side. This is where the hammer curl myth lives, and it does not survive contact with the data.

A 2015 study had 16 people run 20 slow elbow flexions each with pronated, neutral and supinated hands. Biceps activation was statistically identical across all three.

Now the caveat nobody else mentions. Surface EMG cannot cleanly read the brachialis, because it sits underneath the biceps. Nobody actually measured the muscle the myth is about.

The anatomy answers it anyway. The brachialis is the only pure elbow flexor with no rotational job at all, so it works on every curl you do regardless of grip. Grip changes how much help it gets from the biceps, not whether it switches on.

Bar chart of biceps activation by grip position with a callout explaining that surface EMG cannot measure the brachialis

Brachioradialis

The thick cord running from your elbow into your forearm. The 2015 study found it only stood out in a pronated grip, not a neutral one, and the bodybuilder study found supinated actually edged out neutral by about 6 percent.

Blunt version for anyone chasing forearm size: a reverse curl is the grip change that shows up in the testing. A hammer grip is not.

Which Head Does It Target?

The short head. Because your shoulder is flexed forward over the pad, the long head is pre-shortened and cannot contribute much, so the load dumps onto the inner head. The 2009 EMG work found the same thing.

How To Do Preacher Hammer Curls

Most people’s first set ends with a dumbbell thudding into the underside of the pad. Almost nobody tells you why it happens.

Setting Up The Bench

There are two legitimate seat heights, not one rigid rule. Strict means the seat sits low and the top of the pad wedges into your armpit.

Slightly higher, with the pad just beneath your pec, allows a small amount of controlled momentum on heavy sets.

Both work long term. Pick one and stay consistent so your logbook numbers actually mean something.

Before you load anything, run this check:

Sit down and extend your arms fully. Do the dumbbells clear the bottom edge of the pad?
If they clang or catch, raise the seat one notch to change the extension angle.
Armpits flat on the pad, elbows in line with your shoulders and not flaring out.

Then warm up properly. One light feeler set, one at roughly half your working weight, then one to three reps at 75 to 85 percent.

Running The Rep

Hold the dumbbells with palms facing each other and keep them there. No twist at any point in the set.
Lower under control until your forearms pass noticeably below parallel to the floor.
Take about three seconds on the way down. No free-falling into the bottom.
Curl up with your upper arms glued to the pad.
Squeeze at the top without slamming into a locked elbow.
Reset and start the next rep from a dead stop.

Parallel is the peak resistance point, so stopping there skips the hardest part of the rep. Getting below it is the entire reason you sat on the bench.

That bounce out of the bottom is elastic energy in your tendons launching the weight for you. Your arm gets the rep off.

One expectation to set early: a 5 lb jump on this lift feels far bigger than a 5 lb jump on a standing curl. Move up in the smallest increment your gym stocks.

Benefits Of Preacher Hammer Curls

Four reasons hold up after everything above, and the wrist one alone keeps plenty of lifters on the preacher bench.

Removes the cheat: The pad kills the body swing that turns a standing curl into a half-deadlift. Your arm does the work whether it wants to or not, which is why the weight on the dumbbell finally reflects what your arm can actually lift.
It is kinder on the wrists: A fully supinated wrist pinned against a preacher pad is genuinely uncomfortable for a lot of lifters. The neutral grip is the reason plenty of them stay on the preacher bench at all instead of writing the whole station off.
Builds the lower part of the arm: The region between your elbow and where the biceps belly starts responds well to preacher work. That is the stretch of arm that makes a forearm and an upper arm look connected instead of separate, and it is the part most curl programs neglect.
Fills in high biceps insertions: If you have a long gap between your elbow and your muscle belly, more peak work is not the fix. The peak is a front-view thing, and the thickness underneath it is a side-view thing. That thickness comes from the muscle sitting under your biceps, and it takes months of consistent work rather than weeks.

Common Preacher Hammer Curl Mistakes

A popping feeling at the bottom of the rep is the most common complaint about preacher hammer curls, and it usually traces back to one setup error.

Letting your elbows lift off the pad

This sits behind most reported preacher curl elbow pain, usually paired with hyperextending hard at the bottom under load. Film one set from the side and watch the last three reps, because that is where it starts and you will not feel it happening.

Bouncing out of the stretch

The bounce is tendon recoil doing the job your biceps should be doing. It also loads the elbow at its most vulnerable angle, which is exactly where the popping and the pain tend to start.

Range of motion quietly shrinking

Nobody decides to cut their range. It drifts over weeks as loads climb, and lifters end up stopping right at parallel without noticing they ever changed anything. Build in an honest checkpoint: forearms clearly below parallel or the rep does not count.

Fighting the pad instead of adjusting the seat

If the dumbbells hit the pad every rep, that is a seat height problem, not a technique problem. Fix it during setup rather than shortening your reps around it mid-set.

Loading it like a standing curl

The preacher position is mechanically weaker than standing, so carrying your standing hammer curl weight over almost guarantees the elbows come off the pad by rep four. Start lighter than your ego wants and earn it back.

Preacher Hammer Curl Variations And Equipment Options

Lifter performing a rope cable hammer curl with a neutral grip at a cable station

If the dumbbell version keeps hitting the pad, three other setups solve it. One of them fixes the resistance profile complaint from earlier outright.

Variation	Best For	Trade-Off
Dumbbells on a preacher bench	Fixing side-to-side imbalances with no special equipment	Dumbbells collide with the pad, and the top of the rep is nearly weightless
Hammer-grip or EZ bar on the preacher bench	Heavier loading with no pad collision	Fixed hand spacing, and no way to correct a weaker arm
Preacher curl machine with neutral handles	Beginners, and anyone who cheats without meaning to	The cam picks your resistance curve, not you
Single-arm cable rope on a preacher bench	Constant tension through the whole range	Needs a low pulley positioned near the bench

The EZ-bar curls are out-activated dumbbell curls for both the biceps and the forearm across the full rep, so the bar version is not a downgrade in disguise.

Yes, you can do this on a preacher curl machine, as long as the handles are neutral or you can clip a rope to it. The machine strips out momentum better than anything else on the list.

The single-arm cable version is the one the viral critic rates highest for a lengthened resistance profile, which answers the original objection.

Pick by the problem you actually have. Collision means bar or machine, a dead spot at the top means cable, and a weaker left arm means single-arm.

For other preacher-position work, our breakdown of concentration curls vs preacher curls covers where each one fits.

FAQs

Are Preacher Hammer Curls Good For Forearms?

They train the forearm flexors, but a neutral grip is not the forearm upgrade it gets sold as. In controlled testing, a pronated reverse-curl grip is the only change that clearly shifts work toward the forearm. Pick preacher hammer curls for wrist comfort, not for forearm specialization.

Can You Do Hammer Curls On A Preacher Curl Machine?

Yes. Any preacher machine with neutral-grip handles works, and so does a rope attachment on a low cable set up against a preacher pad. The machine removes body momentum almost entirely, though you are locked into whatever resistance curve its cam was built around rather than choosing your own.

Are Preacher Hammer Curls Redundant If I Already Do Preacher Curls?

There is real overlap, and it matters less than most lifters think. Every curl variation trains all three elbow flexors to some degree, so running both is not wasted work. Keep both if you like them, and cut one if your arm day is already crowded.

Why Do My Elbows Hurt After Preacher Hammer Curls?

Usually because your elbows are lifting off the pad, or because you are hyperextending hard at the bottom under a load that is too heavy. Drop the weight, keep your upper arms pinned to the pad, and stop free-falling into the stretch at the bottom of each rep.

What Weight Should I Start With On Preacher Hammer Curls?

Beginners typically handle around 45 to 55 pounds total on a preacher bar, so your per-dumbbell number will look small on paper. Start well below your standing hammer curl weight and add the smallest increment your gym stocks. The preacher position is mechanically weaker than standing, and that is normal.

Bottom Line

The viral critique gets one thing right and one thing wrong. It is right that a free-weight preacher hammer curl is brutal at the bottom and nearly free at the top.

It is wrong that this makes the exercise pointless, because the preacher position is what grows the lower third of the arm.

Keep them if the neutral grip is what lets your wrists tolerate preacher work, or if you want the lower half of your arm to catch up to your biceps.

Swap to a standing or cable hammer curl if you want steady tension through the entire range.

Grip choice is a rounding error next to whether you train the lift hard enough and often enough for it to matter.

Plenty of lifters built thick forearms on hammer curls while the studies were still arguing about them.

Run them for eight weeks in the 8 to 12 range. Judge them on a tape measure, not on a video.