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Hammer Curl

Draftstrength50%beginner⬤ limited evidence
View FHIR resourceFHIR R4 ActivityDefinition — the interoperable form of this exercise

Positions & Range of Motion

Start
standing, a dumbbell in each hand at the sides in neutral grip (palms facing thighs, thumbs up), elbows fully extended and pinned to the ribs
End
elbows flexed to curl the weights toward the shoulders with thumbs still up, then lowered over ~3 s to full extension
Range of Motion
0 to ~140° elbow flexion; forearm held in neutral rotation

How to Perform

Stand holding a dumbbell in each hand at your sides with palms facing your thighs (neutral grip). Keeping the elbows pinned to your ribs and the thumbs pointing up throughout, bend the elbows to curl the weights toward the shoulders, then lower with control back to full elbow extension.

Watch on YouTube↗

Opens a YouTube search for “Hammer Curl”

Equipment:dumbbells
Starting position: standing

Coaching Cues

  1. 1

    Hold the dumbbells like hammers — thumbs up, palms facing each other the whole time.

    (setup)
  2. 2

    Imagine your elbows are pinned to your ribs with a strap; only your forearms move.

    (external)
  3. 3

    Bring the top of the dumbbell toward your shoulder without letting the weight tip forward or back.

    (external)
  4. 4

    Lower for a slow count of three until the arm is fully straight — no dropping the weight.

    (tempo)

Evidence-Based Dosing & EMG Data

Recommended Dosing

2-4 sets of 8-12 repetitions at a moderate load (roughly 65-80% 1RM or 2-3 reps in reserve), 2-3 sessions per week, consistent with general resistance-training guidelines for hypertrophy and strength; no hammer-curl-specific dosing trials exist.

EMG Activation Data

Surface EMG comparisons of curl grip positions indicate that a neutral (hammer) grip produces relatively higher brachioradialis activation and somewhat lower biceps brachii activation than a supinated grip, because the biceps loses mechanical advantage as a supinator-flexor when the forearm is held in mid-position. The brachialis, inserting on the ulna, flexes the elbow irrespective of forearm rotation and is strongly recruited in all curl variants. Wrist flexors and extensors co-contract isometrically to keep the wrist neutral, and finger flexors work isometrically for grip. Overall the direct EMG literature on hammer curls specifically is sparse; most inferences come from studies of elbow-flexion tasks at varying forearm rotations.

Muscles Involved (10)

Primary Movers

Brachioradialis— The neutral (thumbs-up) grip places the brachioradialis in its strongest line of pull, making it a featured mover compared with supinated curls.
Brachialis— Pure elbow flexor regardless of forearm rotation; loaded heavily in all curl variants and unaffected by the neutral grip.

Secondary Movers

Biceps Brachii— Still an active elbow flexor, but at a relative mechanical disadvantage in neutral forearm rotation versus a fully supinated grip.

Stabilizers

Anterior Deltoid— Stabilizes the humerus against the flexion moment of the load; should not actively swing the shoulder.
Flexor Digitorum Superficialis— Isometric grip on the handle to hold the dumbbell; secures the implement rather than producing elbow flexion, so it is a stabilizer, not a synergist of the movement.
Flexor Digitorum Profundus— Isometric grip on the handle; secures the load rather than contributing to elbow flexion, so it is a stabilizer, not a synergist.
Flexor Carpi Ulnaris— Co-contracts with wrist extensors to hold the wrist in neutral under load.
Extensor Carpi Radialis Longus— Prevents the wrist from collapsing into flexion as the load increases.
Upper Trapezius— Low-level scapular support; watch for compensatory shrugging with heavy loads.

Lengthened / Stretched

Triceps Brachii— Antagonist that lengthens through the concentric curl and controls the elbow eccentrically on the lowering phase.

Easier Variations ↓

1

Seated Alternating Hammer Curl

Sit with back supported and curl one arm at a time with a lighter dumbbell; the seat eliminates trunk sway and alternating arms halves the systemic demand.

2

Band Hammer Curl

Stand on a resistance band and curl with a neutral grip; the ascending band resistance is lightest at the weakest joint angle and is easy to titrate for deconditioned or post-injury patients.

Harder Variations ↑

1

Cross-Body Hammer Curl

Curl the dumbbell across the torso toward the opposite shoulder, further biasing the brachioradialis and brachialis and allowing heavier loads.

2

Eccentric-Emphasis Hammer Curl

Use a heavier load, assist the concentric with the opposite hand or momentum, then perform a 4-5 second controlled lowering to overload the eccentric phase.

Target Movements (1)

Elbow FlexionHumeroulnar Joint

Why This Exercise Matters

Everyday activities this exercise helps you do — essential means it directly trains the capacity the task needs:

Carrying and Lifting ObjectsPulling (Doors, Drawers)

Goals This Helps With

Rehab, performance, prevention, and mobility goals this exercise supports — essential means it's a cornerstone:

Improve Your Pull-Upperformance

Research Notes

claude-researched 2026-07; muscle/movement links validated against the roster. Adversarial clinical verification pending — do not promote past needs_review without human review.