EZ-Bar Skullcrusher

The EZ-bar skullcrusher is performed supine on a bench with the EZ-bar lowered from arms-extended overhead toward the forehead. The fixed shoulder position at ~90° flexion places all three triceps heads in a moderately lengthened position while elbow extension provides the isolated triceps stimulus. The EZ-bar's semi-pronated grip reduces wrist stress compared to a straight bar.

Execution

1. Lie on a flat bench; hold an EZ-bar with a close grip (inner knurling), arms extended perpendicular to the floor
2. Keep the upper arms vertical and stationary; lower the bar by bending the elbows only
3. Lower until the bar is just above the forehead — the "skull" reference point
4. Extend the elbows to return to the start; keep the upper arms stationary throughout
5. Do not lock out forcefully at the top; maintain muscular tension

What the EMG Data Shows

Two studies with different normalization methods:

Study	Measurement	Triceps Long	Triceps Lateral
Brettler 2023	True %MVIC, 65% 1RM	23.79% ± 9.19%	—
Boehler 2011	Normalized (not %MVIC)	70% ± 20.9%	55% ± 14.1%

The Brettler 2023 value (23.79% MVIC) appears low because: (1) the load was 65% 1RM, not maximal; (2) the MVIC reference is an isometric maximal contraction, which produces different neural drive than dynamic lifting. The Boehler 2011 values are relative to the triangle push-up baseline within that study.

Shoulder Position Comparison

Exercise	Shoulder	Long Head Length
Skullcrusher	90° flexion	Mid-range
Overhead extension	180° flexion	Maximum
Pushdown	0° (neutral)	Minimum

The skullcrusher trains the long head in a mid-length position — more stimulus than a pushdown, less than an overhead extension. For comprehensive triceps development, pair with an overhead variation.

For system-specific training applications, see each system's lens entry.