Preacher Curl EZ Bar: How To, Muscles Worked & Common Mistakes

The preacher curl is one of the best exercises for pure biceps isolation. What makes it unique is the preacher bench itself — by bracing your upper arms against the angled pad, all possibility of swinging or using body momentum is eliminated. Every single rep has to be completed by your biceps alone, which makes it brutally effective for building size and peak.

It’s a favourite among bodybuilders for good reason — if you want that sharp biceps peak, the preacher curl is one of the best tools for the job.

Why the Preacher Curl Is Different from Other Curls

Most standing curl variations allow at least some degree of momentum or body movement to assist the lift. The preacher bench completely removes this by fixing your upper arms in place. This means:

• No cheating — your biceps have to do all the work on every rep
• Constant tension at the bottom — the angled pad keeps your biceps loaded even at the bottom of the movement where standing curls often lose tension
• Greater stretch — the forward angle of the pad puts your biceps in a more stretched position at the bottom, which is excellent for muscle development

Check out our Barbell Curl page for the standing variation and a full comparison.

Preacher Curl – Muscles Worked

Primary muscles:

• Biceps brachii (short head) — the inner head of the bicep is particularly targeted due to the forward arm position on the pad
• Brachialis — heavily worked throughout the curl, adds thickness underneath the bicep

Secondary muscles:

• Brachioradialis — forearm muscle that assists with the curl
• Forearm flexors — work to maintain grip throughout the set

How to Perform the Preacher Curl

1. Sit at the preacher bench and adjust the seat height so the top of the pad fits snugly in your armpits when your arms are resting on it.
2. Pick up the EZ bar with an underhand grip on the inner angled handles — this is the most wrist-friendly grip for most people.
3. Let your arms extend down the pad until they are almost fully extended — this is your starting position. Don’t lock your elbows out completely.
4. Curl the bar upward by bending your elbows, keeping your upper arms flat against the pad throughout — don’t let them rise up.
5. Curl until your forearms are roughly vertical or slightly past — squeeze your biceps hard at the top.
6. Lower the bar back down slowly over 2–3 seconds until your arms are almost fully extended again.
7. Repeat for your desired reps.

Pro tip: The most dangerous point of this exercise is at the very bottom of the rep. Fully locking out your elbows under load with your arms in this forward-angled position puts significant stress on the elbow tendons. Stop just short of full extension at the bottom — keep a very slight bend to protect the joint.

Preacher Curl – Sets & Reps

Preacher Curl – Common Mistakes to Avoid

1. Fully locking out at the bottom As mentioned above — this is the most important safety point with preacher curls. Snapping your elbows to full extension at the bottom under load puts your elbow tendons under extreme stress and is a common cause of bicep tendon injuries. Always keep a slight bend at the bottom.

2. Upper arms lifting off the pad If your upper arms are rising off the pad as you curl, you’re using your shoulders to help — which defeats the purpose of the preacher bench entirely. Keep your upper arms flat against the pad throughout every rep.

3. Going too heavy The preacher bench eliminates all momentum which makes the weight feel much heavier than on standing curls. Most people need to use significantly less weight here than on barbell curls — and that’s completely fine. The isolation is the point.

4. Rushing the lowering phase The slow eccentric is especially important on preacher curls because of the stretched position at the bottom. Lower deliberately over 2–3 seconds and feel the tension through the full range.

5. Wrong seat height If the pad is too low your shoulders shrug up, too high and your elbows lift off. The top of the pad should fit right into your armpits — take time to adjust the seat properly before every set.

EZ Bar vs. Straight Bar vs. Dumbbell

The preacher curl can be done with several different implements:

• EZ bar Preacher Curl — the most common and recommended option for most people. The angled grip reduces wrist and elbow stress while still delivering excellent bicep activation
• Straight barbell Preacher Curl — maximum supination, slightly more bicep activation but can cause wrist discomfort for some people
• Dumbbell (single arm) Preacher Curl — allows unilateral work, great for fixing strength imbalances, and allows your wrist to rotate naturally throughout the movement for a more comfortable feel

Where It Fits in Your Workout

The preacher curl is a strict isolation exercise and works best in the middle or toward the end of your biceps session — after your heavier compound curling work like barbell curls. Because it eliminates all momentum, it’s excellent for finishing off your biceps with pure isolation volume when the muscles are already partially fatigued.