Skullcrusher (Lying Triceps Extension)

Skullcrusher (Lying Triceps Extension): Sculpting the Long Head for Maximum Arm Size

If the Close-Grip Bench Press is the triceps’ compound powerhouse, the Skullcrusher is its precision sculptor — the isolation exercise that builds shape, separation, and that unmistakable horseshoe sweep on the back of the upper arm.

Known technically as the Lying Triceps Extension, the Skullcrusher directly targets the long head of the triceps, which gives the arm its full, rounded appearance from every angle. For bodybuilders, it’s an essential move — one that brings detail to brute mass and polish to raw power.

When executed correctly, it delivers deep stretches, powerful contractions, and unmatched muscle isolation.

When performed carelessly, however, it can wreck elbows or shoulders. Mastering it means mastering control, precision, and triceps connection.

Let’s break down how to perform it, program it, and use it to turn your upper arms into armor plating.

Muscles Worked

Primary:

• Triceps brachii — especially the long head, with secondary emphasis on lateral and medial heads.

Secondary:

• Forearm extensors (stabilization)
• Core (isometric brace)

👉 The long head is the only triceps portion that crosses the shoulder joint. This means any movement that combines shoulder extension and elbow extension — like the Skullcrusher — hits it more deeply than pressing alone.

Why Bodybuilders Swear by Skullcrushers

1. Targeted Long-Head Development
   • Presses hit all triceps heads, but Skullcrushers isolate the long head for that thick, horseshoe silhouette.
2. Superior Stretch Under Load
   • The deep range of motion elongates muscle fibers, stimulating more hypertrophy.
3. Perfect Isolation for Shape & Definition
   • Minimal shoulder or chest involvement — all triceps, all the time.
4. High Versatility
   • Works with barbells, dumbbells, cables, or machines, adapting to any gym setup.
5. Aesthetic Impact
   • Builds the upper-arm curve visible from the side and rear — the “3D arm” effect.

How to Perform the Skullcrusher (EZ-Bar Version)

Setup

1. Bench Position
   • Lie flat on a bench with your head near the top edge so the bar can move freely behind it.
2. Grip
   • Use an EZ-bar with a narrow or medium grip (palms angled inward).
   • Wrists remain neutral and aligned with elbows.
3. Body Position
   • Feet flat, glutes and shoulders anchored to the bench.
   • Arms fully extended above the chest, perpendicular to the floor.

Execution

1. Lowering Phase
   • Inhale and slowly bend at the elbows, keeping upper arms fixed.
   • Lower the bar toward your forehead (traditional style) or slightly behind the head (safer, better stretch).
   • Stop just before the bar touches — full stretch without elbow strain.
2. Extension Phase
   • Exhale and extend the elbows, driving the bar back to the start position.
   • Keep the upper arms stationary; only the forearms move.
   • Squeeze the triceps hard at lockout for 1–2 seconds.
3. Repeat
   • Maintain a smooth tempo, full control, and constant tension.

Breathing

• Inhale during the lowering phase.
• Exhale during the extension and lockout.

Key Form Cues

✅ Keep elbows pointed to the ceiling — no flaring.
✅ Move only the forearms; upper arms stay still.
✅ Don’t drop the bar directly onto the forehead — aim slightly behind the head.
✅ Use moderate weight with perfect control.
✅ Squeeze the triceps fully at the top of every rep.

Common Mistakes and Fixes

Variations and Alternatives

1. Dumbbell Skullcrusher
   • Allows independent arm movement; excellent for correcting imbalances.
   • Use neutral or rotating grip to reduce joint stress.
2. Incline Skullcrusher
   • Perform on a 30–45° incline bench to increase long head stretch.
3. Decline Skullcrusher
   • Slightly shortens the range but targets the lateral head more directly.
4. Cable Lying Triceps Extension
   • Provides constant tension through the range of motion.
5. Overhead Cable Extension (Seated or Standing)
   • Similar motion but emphasizes the stretch under continuous load.
6. EZ-Bar Seated Extension (French Press)
   • Vertical variation; great for pairing with presses in supersets.
7. Machine Lying Triceps Extension
   • Excellent for joint-friendly training or controlled hypertrophy work.

Programming Guidelines

For Hypertrophy (Muscle Growth)

• Sets: 3–4
• Reps: 10–15
• Rest: 60–90 seconds
• Tempo: 3s down, 1s up
• Goal: Deep stretch and peak contraction — moderate weight, high control.

For Strength & Density

• Sets: 4
• Reps: 6–8
• Rest: 2 minutes
• Tempo: Controlled eccentric, powerful concentric.
• Goal: Overload the triceps while maintaining form integrity.

For Endurance / Pump

• Sets: 3
• Reps: 15–20
• Rest: 45 seconds
• Goal: Flood the triceps with blood for maximal metabolic stress.

Integration into Training

Example Arm Day

• Close-Grip Bench Press – 4×8
• EZ-Bar Skullcrusher – 3×10–12
• Overhead Cable Extension – 3×15
• Rope Pushdown – 3×15–20
• Dumbbell Hammer Curl – 3×12

Example Push Day

• Bench Press – 4×6
• Overhead Press – 3×8
• Incline Dumbbell Press – 3×10
• Skullcrusher – 3×12–15
• Lateral Raise – 3×15

Example Triceps Superset

• Skullcrusher – 10–12 reps
• Rope Pushdown – 12–15 reps
• (Rest 60 sec between supersets)

Advanced Training Strategies

1. Stretch Overload Technique
   • Pause at the bottom stretch for 1–2 seconds each rep to amplify tension on the long head.
2. Reverse Pyramid Sets
   • Begin with your heaviest set (6–8 reps), then reduce weight each set and increase reps (10–12, 12–15).
3. Partial Reps
   • After failure, perform 3–5 half reps from the bottom stretch to extend time under tension.
4. Mechanical Drop Sets
   • Switch from lying Skullcrusher → Close-Grip Press without rest.
5. Tempo Manipulation
   • 4-second eccentric lowers to boost hypertrophy and tendon resilience.

Bodybuilder’s Tips

💡 Rotate Grip for Comfort: Use an EZ-bar or dumbbells to reduce wrist and elbow stress.
💡 Keep Upper Arms Still: Think of the elbow joint as the only hinge.
💡 Stretch and Contract: Don’t rush; the long head grows from stretch tension.
💡 Don’t Ego Lift: Precision trumps plates — it’s a shaping movement.
💡 Pair with Compounds: Follow a heavy press with Skullcrushers for full triceps recruitment.

Strength vs Aesthetic Focus

Safety & Joint Health

• Warm up elbows thoroughly before heavy triceps work.
• Avoid locking out aggressively at the top.
• Use joint-friendly grips (EZ-bar, dumbbell, or cable).
• Don’t allow elbows to drift excessively backward — maintain vertical forearms.
• Stretch triceps and forearms post-session.

Practical Takeaways

• The Skullcrusher is the premier long-head builder — prioritize it in your triceps routine.
• Lower the bar behind your head, not onto your forehead, for safety and stretch.
• Focus on form, control, and full range, not maximum load.
• Pair with compound presses for complete triceps coverage.
• Incorporate variations (incline, cable, dumbbell) to prevent adaptation.

Conclusion

The Skullcrusher is a bodybuilding classic for a reason — it isolates the triceps in a way no compound press can, carving depth, detail, and raw thickness into the arms. It’s the definition of precision training: slow, controlled, and devastatingly effective.

For lifters chasing balanced, powerful arms, it’s a non-negotiable movement. Train it consistently, focus on the stretch and squeeze, and your triceps will take on that dense, three-dimensional shape that separates the good from the great.

Respect the movement, control every inch, and the Skullcrusher will reward you with arms that command attention — both in the gym and on stage.