Arms · Isolation
Preacher Curl Machine
The preacher curl machine is a seated biceps exercise where your upper arms rest on an angled pad while you curl a handle attached to a weight stack. The pad fixes the arms in front of the body, removing swinging and loading the biceps hard near the stretched bottom. It is one of the strictest biceps exercises available.
Also known as: Machine preacher curl, Seated preacher curl machine, Biceps preacher machine, Preacher curl
- Muscle group
- Arms
- Movement pattern
- Isolation
- Type
- Isolation
- Equipment
- Preacher curl machine
- Difficulty
- Beginner
What muscles does the preacher curl machine work?
Primary movers
- Biceps brachii
- Brachialis
Assisting muscles
- Brachioradialis
- Forearm flexors
Resting the upper arms on an angled pad places the shoulders in front of the body, which slightly shortens the long head of the biceps and puts relatively more emphasis on the short head and the brachialis.
The machine's cam is designed to keep resistance relatively even across the curl, and most preacher machines load the bottom of the movement noticeably. That means the biceps work hard when they are lengthened, a position linked to strong growth responses.
Because the pad supports your arms and the seat supports your body, there is no way to swing or lean. Every rep is done by the elbow flexors alone, which makes the preacher machine a good choice when you want to train the biceps to failure safely.
The brachialis works hard in any curl but is particularly loaded in the preacher position, so the machine builds arm thickness as well as the biceps.
How to do the preacher curl machine
Setup
- 1
Adjust the seat so your armpits sit snugly over the top edge of the pad.
- 2
Sit down and rest the backs of your upper arms flat on the pad.
- 3
Line up your elbows with the machine's pivot point, usually marked on the side.
- 4
Take an underhand grip on the handles with your arms nearly straight.
Execution
- 1
Curl the handles up towards your shoulders by bending the elbows.
- 2
Keep the backs of your arms on the pad throughout the rep.
- 3
Squeeze the biceps at the top, stopping just before the forearms reach vertical.
- 4
Lower over two to three seconds until your arms are almost fully straight.
- 5
Avoid locking out hard at the bottom, where the elbows are most exposed.
- 6
Keep your chest against the pad and your hips on the seat.
Common preacher curl machine mistakes
Wrong seat height
A seat set too low makes you reach over the pad with your shoulders rolled forward. Too high and the pad digs into your arms near the elbow.
The fix: Set the seat so the top of the pad sits in your armpits and your upper arms lie flat along it.
Elbows misaligned with the pivot
Sitting too far forward or back so the elbows do not line up with the machine's axis. The resistance curve feels wrong and the elbows take odd stress.
The fix: Line your elbow joint up with the machine's pivot marker before the first rep.
Dropping the weight at the bottom
Letting the handles fall into the bottom position, which shocks the elbows and skips the stretched part of the rep.
The fix: Lower slowly through the full range. The bottom third is the most valuable part of the movement.
Lifting the arms off the pad
Raising the elbows off the pad to finish heavy reps, which recruits the shoulders and defeats the purpose of the machine.
The fix: Keep the arms planted. If you cannot finish the rep without lifting, end the set there.
How many sets and reps?
| Goal | Sets | Reps | Load | Rest |
|---|---|---|---|---|
| Hypertrophy | 3 | 10–15 | Moderate, 0–2 RIR | 60–90 s |
| Strength | 3–4 | 6–10 | Heavy | 90 s–2 min |
| Intensity finisher | 1–2 | 12–15 plus drop set | Moderate, to failure | 90 s |
Because the machine controls the path and removes any cheating, it is one of the safest places to take biceps sets to failure or to use drop sets. Two to three sets after a free-weight curl works well. Count the machine towards your weekly biceps volume, which for most people sits around six to twelve direct sets.
Running the preacher curl machine in your next block? Hercules logs every set, shows last session's numbers before you lift, and suggests when to add weight.
Get it on Google PlayPreacher Curl Machine variations and alternatives
Barbell Preacher Curl
AlternativeThe free-weight version on a preacher bench. More load at the bottom, less at the top.
EZ Bar Curls
AlternativeStanding, wrist-friendly curl that lets the shoulders sit at the sides and loads the long head more.
Dumbbell Hammer Preacher Curls
AlternativeNeutral grip on a preacher bench shifts the emphasis towards the brachialis and brachioradialis.
Bicep Curl Machine
AlternativeMany gyms label their preacher machine as a biceps curl machine. Same principle, slightly different arm angle.
Frequently asked questions
What does the preacher curl machine work?
Mainly the biceps brachii and brachialis. The arm position places a little more emphasis on the short head of the biceps and the brachialis than a standing curl, and the fixed pad removes any help from the shoulders or torso.
Is the preacher curl machine better than free weights?
It is stricter and easier to take to failure safely. Free weights allow more variety in angle and grip. Many people use a free-weight curl first and the machine after, to push the biceps hard once they are fatigued.
How should I set up the preacher curl machine?
Adjust the seat until your armpits sit over the top of the pad and your upper arms lie flat. Then line your elbows up with the machine's pivot point. A correct setup makes the resistance feel smooth through the whole range.
Why do preacher curls hurt my elbows?
The bottom position stretches the biceps tendon under load, and dropping into it or locking out hard magnifies that stress. Lower slowly, stop just short of full lockout, and use moderate weights.
Should I do preacher curls one arm at a time?
Many machines allow it, and single-arm sets help even out strength differences between the arms. Two-arm sets are quicker. Both are effective.
Hercules tracks every preacher curl machine you log, shows you last session's numbers before you lift, and flags when your progress stalls.
Get it on Google Play