Hammer Curl: Build Bigger Arms with This Brachialis Builder

The hammer curl uses a neutral grip — thumbs up, palms facing each other — instead of the supinated (palms up) grip of regular curls. This simple change shifts emphasis to the brachialis and brachioradialis, building arm thickness that regular curls miss.

If you want arms that look impressive from every angle, hammer curls are non-negotiable.

Why Hammer Curls?

Brachialis Development

The brachialis sits underneath the biceps. When developed, it pushes the bicep up and out, making your arms look thicker. Hammer curls are one of the best brachialis builders.

Forearm Involvement

The brachioradialis (the meaty part of your outer forearm) works hard during hammer curls. You get bicep and forearm work in one movement.

Comfortable Grip

Many lifters find the neutral grip more comfortable on their wrists and elbows than supinated curling. If regular curls bother your joints, hammers often feel better.

Functional Strength

The neutral grip mimics how you naturally pick things up. Hammer curl strength transfers well to real-world activities.

Heavier Loading

Most people can hammer curl more than they can regular curl. The grip position allows for heavier training.

Muscles Worked

Primary:

• Brachialis (under the bicep)
• Brachioradialis (outer forearm)
• Biceps brachii (still works, just less emphasis)

Secondary:

• Forearm flexors
• Grip muscles

Hammer Curl Technique

Setup

1. Dumbbells: One in each hand
2. Grip: Neutral (palms facing each other, thumbs up)
3. Stance: Hip width, slight knee bend
4. Posture: Tall spine, shoulders back
5. Arms: Extended at sides

The Curl

1. Initiate: Curl dumbbells up by flexing elbows
2. Path: Dumbbells come up beside your body (not across)
3. Grip: Maintain neutral grip throughout — thumbs stay up
4. Elbows: Stay pinned at your sides
5. Peak: Curl until full elbow flexion

The Lower

1. Control: Lower slowly (2-3 seconds)
2. Full extension: Return to starting position
3. Don't swing: No momentum at bottom
4. Maintain grip: Thumbs stay up throughout

Key Form Points

| Point | Why It Matters | |-------|---------------| | Thumbs up throughout | Defines the hammer curl | | Elbows pinned | Prevents cheating | | Controlled tempo | Maximizes muscle work | | Full range of motion | Complete contraction and stretch | | Both arms or alternating | Both work, choose your preference |

Common Mistakes and Fixes

Rotating to Supinated Grip

The problem: Hands rotate so palms face up at the top, turning it into a regular curl.

Why it happens: Habit, not understanding the exercise.

The fix:

• Keep thumbs pointing up the entire time
• Think "hammer" — like holding a hammer
• The grip never changes

Swinging

The problem: Using body momentum to help curl the weight.

Why it happens: Weight too heavy, trying to lift more.

The fix:

• Keep body stationary
• Reduce weight
• Only your forearms move

Bringing Dumbbells Across Body

The problem: Curling across the body instead of straight up.

Why it happens: Trying different angles (which is fine for cross-body hammer curls, but that's a different variation).

The fix:

• Standard hammer curls go straight up, dumbbells beside your body
• Cross-body is a separate variation with different emphasis

Elbows Drifting Forward

The problem: Elbows come forward as you curl.

Why it happens: Trying to help the movement or lift more.

The fix:

• Pin elbows at your sides
• Upper arm doesn't move
• Reduce weight if needed

Hammer Curl Variations

Alternating Hammer Curl

One arm at a time, alternating. Allows more focus per arm, slight core engagement.

Simultaneous Hammer Curl

Both arms curl together. More time efficient, easier to maintain rhythm.

Seated Hammer Curl

Sitting on bench. Reduces ability to cheat, more isolated.

Incline Hammer Curl

On incline bench (45-60°). Increases stretch on biceps and brachialis.

Cross-Body Hammer Curl

Curl across your body toward opposite shoulder. Different brachialis angle, some prefer this feel.

Rope Hammer Curl

Using cable with rope attachment. Constant tension, neutral grip maintained naturally.

Preacher Hammer Curl

On preacher bench with neutral grip dumbbells. Maximum isolation, no cheating possible.

Programming Hammer Curls

For Arm Thickness

• 3-4 sets of 10-12 reps
• Moderate weight, strict form
• Focus on brachialis squeeze

For Strength

• 4 sets of 6-8 reps
• Heavier weight (hammer curls allow this)
• Full recovery between sets

As Part of Bicep Training

• 3 sets of 10-12 reps
• After standard bicep curls
• Ensures complete arm development

For Forearm Development

• 3-4 sets of 12-15 reps
• Moderate weight
• Focus on brachioradialis engagement

Frequency

• 1-2x per week
• Include with bicep or arm training
• Can replace or supplement regular curls

Sample Workouts with Hammer Curls

Workout 1: Complete Biceps

1. Barbell Curl — 4x8 (biceps)
2. Incline Curl — 3x10 (long head)
3. Hammer Curl — 3x12 (brachialis)
4. Concentration Curl — 2x15 (peak)

Workout 2: Arm Thickness Focus

1. Close-Grip Bench — 4x8
2. Hammer Curl — 4x10
3. Tricep Pushdown — 3x12
4. Reverse Curl — 3x12

Workout 3: Pull Day Arms

1. Pull-ups — 4x8
2. Barbell Row — 4x8
3. Face Pulls — 3x15
4. Hammer Curl — 3x12
5. Spider Curl — 2x15

Workout 4: Superset Arms

Hammer Curl — 12 reps Superset with: Skull Crushers — 12 reps 4 rounds

Hammer Curl vs Regular Curl

| Factor | Hammer Curl | Regular Curl | |--------|-------------|--------------| | Grip | Neutral (thumbs up) | Supinated (palms up) | | Primary muscle | Brachialis | Biceps | | Forearm involvement | Higher | Lower | | Bicep peak emphasis | Lower | Higher | | Weight potential | Higher | Lower | | Wrist comfort | Usually better | Can be stressful | | Arm thickness | Better | Moderate | | Arm peak | Moderate | Better |

Use both: Regular curls for bicep peak, hammer curls for thickness. Together they create complete arm development.

Who Should Do Hammer Curls

Great For

• Anyone wanting thicker arms
• Lifters with wrist or elbow issues
• Those wanting forearm development without isolation
• People looking to lift heavier on curls
• Anyone seeking complete arm development

Not Ideal For

• If you can only do one curl variation (regular curls hit biceps more directly)
• Those who already have overdeveloped brachialis (rare)

Everyone Should Include

Hammer curls belong in virtually every arm training program. The brachialis development they provide can't be replicated by regular curls alone.

The Bottom Line

The hammer curl builds arm thickness by targeting the brachialis and brachioradialis that regular curls miss. The neutral grip is comfortable, allows heavier loading, and creates complete arm development.

Keep your thumbs up throughout. Don't rotate the grip. Control the movement and feel the brachialis working.

Add hammer curls to your arm training for thickness that shows from every angle.

---

Related:

• Best Bicep Exercises
• Reverse Curl Guide
• Incline Dumbbell Curl Guide
• Bicep Curls Complete Guide