Preacher Hammer Curl

The preacher hammer curl is a specialized arm exercise that combines the stability of the preacher bench with the neutral grip of the hammer curl. This variation isolates the brachialis — the muscle beneath the biceps — and the brachioradialis in the forearm, promoting thicker upper arms and improved elbow flexion strength. By preventing torso swing and upper-arm movement, it allows for focused contraction and tension on these often-neglected muscles.

History and Origins of the Preacher Hammer Curl

The preacher bench was popularized in the 1960s by legendary bodybuilders to enforce strict curling form and reduce cheating. The hammer grip, historically used in strongman and manual labor contexts, gained traction in bodybuilding for its ability to activate the brachialis and forearm stabilizers. Combining these two concepts created an exercise prized for its isolation benefits and joint-friendly mechanics.

How to Perform the Preacher Hammer Curl

Setup

1. Bench Adjustment: Set the preacher bench pad height so that your armpits rest comfortably at the top of the pad when seated.
2. Bar Selection: Use a neutral-grip (hammer) EZ-bar, dumbbells, or a hammer curl handle.
3. Grip & Position: Sit with chest pressed against the pad, arms extended over the pad, and palms facing each other.

Execution

1. Curl Up: Flex your elbows to raise the weight, keeping wrists neutral and upper arms pinned to the pad.
2. Peak Contraction: Pause at the top, squeezing the brachialis and forearm muscles.
3. Lower: Lower under full control until arms are nearly locked out, feeling the stretch in the forearm and brachialis.

Imagine sitting steady on the preacher bench, forearms placed firmly on the pad. As you curl, you think only of your elbow joint, moving the weight upward in a strict, vertical path. Your torso remains still, and the neutral grip keeps your wrists aligned. At the top, you hold the contraction, then reverse slowly, maximizing tension and protecting the joints.

Muscle Group Targeted

• Primary: Brachialis
• Secondary: Brachioradialis, Biceps Brachii (short head)

Because the neutral grip removes the supination component of a traditional curl, the brachialis bears the brunt of the load. The brachioradialis in the forearm also works strongly to support the movement.

Effectiveness Breakdown

1. Stretch and Tension

The preacher position prevents momentum and ensures the muscle works through a full range of motion. The neutral grip maintains constant tension on the brachialis and forearm throughout both concentric and eccentric phases.

2. Safety

Eliminating shoulder and torso involvement reduces risk of injury. The pad supports the upper arm, and the neutral grip minimizes wrist stress compared to supinated curls.

3. Progressive Overload Potential

This variation allows for precise load increments with dumbbells or EZ-bar plates. Tempo variations (e.g., 3-1-3) and static holds at peak contraction offer additional overload strategies.

Programming Recommendations

• Frequency: 1–2× per week on arm or pull-focused days
• Volume: 3–4 sets of 8–12 reps
• Load: Moderate; choose a weight allowing 2–3 RIR (reps in reserve)
• Progression: Increase reps before adding weight; incorporate slow eccentrics or paused reps

Coaching Tips

• "Pin your elbows to the pad": Prevents cheating and isolates the brachialis.
• "Keep wrists neutral": Avoid bending the wrist to maintain tension on the target muscles.
• "Control the negative": A 3-second lowering phase enhances muscle damage and growth stimulus.
• "Pause at peak": Hold for 1–2 seconds to reinforce mind-muscle connection.
• "No torso lean": Keep your core tight and back flat against the bench for perfect form.

Mistakes to Avoid

• Elevating the elbows: Lifts arms off the pad and shifts tension away from the brachialis.
• Swinging the body: Reduces isolation and increases momentum rather than muscle work.
• Using a supinated grip: Engages biceps more than brachialis, defeating the variation’s purpose.
• Dropping too fast: Loss of eccentric control reduces hypertrophic stimulus and may risk injury.
• Overloading prematurely: Heavy weights break form; prioritize perfect technique first.

Scientific Insights

Research shows that neutral-grip curls activate the brachialis significantly more than supinated curls (Lehman et al., 2005). Additionally, preacher bench support reduces accessory muscle recruitment, focusing load on the target muscle — a principle supported by EMG studies on isolation movements (Schoenfeld, 2010).

Final Thoughts

The preacher hammer curl is a prime exercise for developing arm thickness and forearm strength. Its strict mechanics and ergonomic grip make it both safe and effective for lifters of all levels. Add it to your arm routine to ensure complete development of the elbow flexors and achieve balanced, powerful arms.

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References

1. Lehman, G. J., et al. (2005). EMG analysis of the biceps and brachialis during supinated, pronated, and neutral grip curls. Journal of Strength and Conditioning Research.
2. Schoenfeld, B. J. (2010). The mechanisms of muscle hypertrophy and their application to resistance training. Journal of Strength and Conditioning Research.