Barbell Lying Triceps Extension (Skull Crusher)

Barbell Lying Triceps Extension (Skull Crusher): Form, Sets, Tips & FAQ

Barbell Lying Triceps Extension (Skull Crusher): Form, Sets, Tips & FAQ
Upper Arms

Barbell Lying Triceps Extension (Skull Crusher)

Intermediate Barbell + Flat Bench Triceps / Elbow Extension / Hypertrophy
The Barbell Lying Triceps Extension, often called the Skull Crusher, is a classic triceps isolation exercise that trains the elbows to extend under load while keeping the upper arms relatively fixed. It is especially effective for building the long head of the triceps, improving lockout strength, and adding size to the back of the upper arms. The key is a controlled descent, a stable elbow path, and a smooth extension back to the top without turning the rep into a press.

This movement works best when you lower the bar with patience, keep your elbows from drifting excessively, and let the triceps do the work. You should feel strong tension through the back of the upper arms, not discomfort in the wrists, shoulders, or elbows. A slightly tucked elbow position and a steady bar path will usually make the exercise feel smoother and more joint-friendly.

Safety tip: Because the bar travels close to the face and forehead, always use a manageable load, move with control, and stop the set if you lose elbow position or feel sharp elbow pain.

Quick Overview

Body Part Triceps
Primary Muscle Triceps brachii (especially the long head)
Secondary Muscle Anconeus, forearms, shoulder stabilizers
Equipment Barbell or EZ curl bar, flat bench, weight plates, collars
Difficulty Intermediate

Sets & Reps (By Goal)

  • Muscle growth: 3–4 sets × 8–12 reps with controlled lowering and 60–90 sec rest
  • Strength support for pressing: 3–5 sets × 5–8 reps with heavier load and 90–120 sec rest
  • Technique practice: 2–3 sets × 10–15 reps with lighter weight and perfect elbow control
  • Finisher / arm pump: 2–3 sets × 12–15 reps with smooth tempo and short rest

Progression rule: Add weight only when you can keep the bar path controlled, avoid elbow flare, and complete all reps without bouncing or shortening the range.

Setup / Starting Position

  1. Lie flat on a bench: Keep your head, upper back, and glutes supported, with feet planted firmly on the floor.
  2. Grip the bar securely: Use a shoulder-width or slightly narrower grip. Many lifters prefer an EZ curl bar for wrist comfort.
  3. Start above the upper chest: Press or position the bar so your arms are extended and the bar is stable above you.
  4. Set the elbows: Keep the upper arms mostly still and angled so the elbows can bend without drifting excessively.
  5. Brace lightly: Keep your wrists neutral, ribs down, and shoulders packed so the rep stays controlled.

Tip: A small backward angle of the upper arms can help keep tension on the triceps and reduce the tendency to rest at the top.

Execution (Step-by-Step)

  1. Begin from lockout: Hold the bar steady with straight arms above the chest or slightly behind it.
  2. Bend at the elbows: Lower the bar slowly toward the forehead or just behind the head, depending on your preferred variation.
  3. Keep upper arms stable: Avoid turning the rep into a press by minimizing shoulder movement during the descent.
  4. Reach the bottom under control: Stop when you feel a strong triceps stretch and can still maintain clean elbow alignment.
  5. Extend the elbows: Drive the bar back up by contracting the triceps until your arms are straight again.
  6. Reset and repeat: Stabilize the top position briefly before starting the next rep.
Form checkpoint: If the elbows flare wide, the shoulders shift too much, or the bar drops fast toward the forehead, reduce the weight and tighten your tempo.

Pro Tips & Common Mistakes

  • Use a controlled eccentric: The lowering phase should be deliberate, not rushed.
  • Do not flare the elbows early: Keeping them reasonably tucked helps maintain triceps tension.
  • Do not turn it into a close-grip press: Too much shoulder movement reduces isolation.
  • Choose the right bar: An EZ curl bar often feels better on the wrists and elbows than a straight bar.
  • Keep wrists stacked: Avoid letting the wrists fold backward under the load.
  • Use a full but safe range: Lower deep enough for tension, but not so far that you lose control.
  • Train with moderate loads first: This exercise rewards precision more than ego lifting.

FAQ

What muscles do skull crushers work the most?

Skull crushers primarily target the triceps brachii, with strong emphasis on the long head because of the shoulder position and elbow-extension pattern.

Should I lower the bar to my forehead or behind my head?

Both are valid. Lowering slightly behind the head often increases stretch and can feel smoother on the elbows, while lowering toward the forehead is the classic version. Use the path that feels strongest and safest for you.

Is an EZ curl bar better than a straight bar?

For many lifters, yes. An EZ curl bar usually places the wrists in a more natural angle, which can make the exercise more comfortable without changing the basic training effect.

How heavy should I go on barbell lying triceps extensions?

Use a load you can control for the full range without losing elbow position. This exercise is usually more productive with strict, moderate loading than with very heavy sloppy reps.

What is the biggest mistake in this exercise?

The most common mistake is letting the rep become a hybrid press by moving the shoulders too much and losing the isolation effect on the triceps.

Medical disclaimer: This content is for informational and educational purposes only and is not medical advice. If you have persistent elbow, wrist, or shoulder pain, consult a qualified healthcare professional before training through symptoms.

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