Skull Crushers: The Ultimate Triceps-Building Exercise

If your goal is to build thick, powerful arms, then you can’t ignore the importance of training your triceps—the muscle responsible for arm size and pressing strength. And when it comes to effective triceps isolation movements, Skull Crushers reign supreme.

Also known as lying triceps extensions, this exercise is a classic for good reason. With the right form and progression, skull crushers help pack on serious muscle mass to your upper arms while improving performance in all pressing movements.

What Are Skull Crushers?

Skull crushers are a single-joint isolation exercise that primarily targets the triceps brachii. The movement is typically performed lying on a flat or incline bench, lowering a barbell, EZ bar, or dumbbells toward your forehead, then extending the arms to return to the top.

The name “skull crusher” might sound intimidating—but with proper form, this exercise is both safe and incredibly effective.

Muscles Worked

• Primary Muscle: Triceps Brachii (long, medial, and lateral heads)

• Secondary Muscles: Forearms (stabilizers), Deltoids (minimal involvement)

Benefits of Skull Crushers

 Maximum Triceps Activation: Especially the long head, which is often undertrained.
 Increased Arm Size: Adds thickness to the upper arms.
 Improved Pressing Strength: Helps your bench press and overhead press.
 Versatile Equipment Use: Can be performed with barbell, dumbbells, EZ-bar, or cables.
 Easy to Integrate: Fits well in push day or arm day routines.

How to Do Skull Crushers – Step-by-Step

 Equipment Needed:

• EZ Bar (preferred), Straight Barbell, Dumbbells, or Cable Machine

• Flat Bench or Incline Bench

 Execution:

1. Lie flat on a bench with your feet planted firmly.

2. Hold the EZ bar or dumbbells above your chest, arms fully extended.

3. Keep your elbows locked in position—don’t let them flare out.

4. Slowly lower the weight toward your forehead or just behind it.

5. Stop when your elbows reach around 90° or just past.

6. Press the weight back up to the starting position with control.

 Reps & Sets:

• 3–4 sets of 8–12 reps for hypertrophy

• 2–3 sets of 6–8 reps with heavier weight for strength

Common Mistakes to Avoid

 Elbow Flaring: Keep them tucked close to maximize triceps tension.
 Lowering to the Wrong Spot: Aim for forehead or just behind it—not your face or neck.
 Excessive Weight: Go lighter first to master control and form.
 Bouncing the Weight: Control the eccentric (lowering) portion.

Top Variations of Skull Crushers

1. EZ-Bar Skull Crushers – Most wrist-friendly and popular version.

2. Dumbbell Skull Crushers – Allows independent arm movement, fixes imbalances.

3. Incline Skull Crushers – Increases long head activation.

4. Cable Skull Crushers – Constant tension, excellent for finishers.

5. Smith Machine Skull Crushers – Stable and joint-friendly.

Pro Tips to Maximize Gains

• Warm up elbows before heavy sets.

• Use slow negatives (eccentric) for better time under tension.

• Add drop sets or supersets for growth.

• Combine with pushdowns or dips for complete triceps burnout.

Sample Triceps Superset with Skull Crushers

• Skull Crushers (EZ Bar) – 3 sets x 10 reps

• Triceps Rope Pushdowns – 3 sets x 15 reps

• Close-Grip Push-Ups – 2 sets to failure

Great as a finisher on Push Day or Arm Day.

Conclusion

The Skull Crusher is more than just an old-school gym favorite—it’s a science-backed, result-driven exercise that deserves a place in every serious lifter’s routine. It isolates the triceps like few other movements can and helps build both size and pressing power.

Remember: perfect your form, go at your own pace, and crush your triceps goals—without crushing your skull!