Skull Crushers: Complete Guide to the Best Tricep Mass Builder

Skull crushers—also called lying tricep extensions—are one of the most effective exercises for building tricep mass. They target the long head of the triceps, which is often underdeveloped by pushdowns alone.

Here's how to do them safely and effectively.

Why Skull Crushers Work

Long Head Emphasis

The long head of the triceps is the largest of the three heads and is best trained with overhead or stretched positions. Skull crushers put the long head under significant stretch—something pushdowns don't do.

Heavy Loading

Unlike pushdowns, skull crushers allow relatively heavy weights. You can progressively overload more easily for strength and size gains.

Mass Builder

Ask any experienced lifter about tricep mass—skull crushers will be mentioned. They've been a staple for decades for a reason.

Muscles Worked

Primary:

• Triceps (all three heads, emphasis on long head)

Secondary:

• Anconeus (small elbow muscle)
• Shoulders (stabilization)
• Core (stabilization)

How to Do Skull Crushers: Proper Form

Setup

1. Lie on a flat bench with an EZ bar or straight bar
2. Press the weight to arm's length above your chest
3. Arms vertical or slightly angled back toward your head
4. Feet flat on the floor, back flat on the bench

The Movement

1. Lower the bar: Bend only at the elbows, lowering the bar toward your forehead (or just past your head)
2. Keep upper arms still: Only your forearms move
3. Feel the stretch: At the bottom, you should feel a strong stretch in your triceps
4. Extend: Push the bar back up by straightening your elbows
5. Full lockout: Extend arms completely, squeezing triceps

Key Points

• Elbows point up, not out: Keep elbows relatively close together
• Upper arms stay fixed: Don't let elbows drift forward or back during the rep
• Control the descent: Don't actually crush your skull
• Full range of motion: Deep stretch at bottom, full extension at top

Where Should the Bar Go?

There are different approaches:

To the Forehead (Classic)

• Bar lowers to forehead level
• More vertical arm position
• Classic "skull crusher" form

Behind the Head

• Bar lowers past your head, behind you
• Greater stretch on the long head
• Often called "lying tricep extension"
• Generally preferred for tricep development

Recommendation

Lowering behind the head provides a better stretch and more long head activation. Most lifters find this more effective for growth.

Common Skull Crusher Mistakes

1. Elbows Flaring Out

The problem: Elbows point sideways during the movement Why it matters: Reduces tricep isolation, can stress elbows The fix: Keep elbows pointed toward the ceiling, relatively close together

2. Moving the Upper Arms

The problem: Upper arms swing back and forth Why it matters: Turns it into a pullover, reduces tricep work The fix: Lock upper arms in place; only forearms move

3. Going Too Heavy

The problem: Can't control the weight through full ROM Why it matters: Reduced effectiveness, elbow stress, injury risk The fix: Use weight that allows controlled reps with full range

4. Bouncing at the Bottom

The problem: Using momentum to reverse the weight Why it matters: Less muscle tension, more joint stress The fix: Pause briefly at the bottom, controlled reversal

5. Not Getting Full Extension

The problem: Stopping short of lockout Why it matters: Missing peak tricep contraction The fix: Fully extend and squeeze at the top

Elbow Pain and Skull Crushers

Many lifters experience elbow discomfort with skull crushers. Solutions:

Use an EZ Bar

The angled grip is easier on elbows and wrists than a straight bar.

Lower Behind the Head

Going past the forehead often reduces elbow stress.

Reduce Weight, Increase Reps

Lighter weight with more reps is often more elbow-friendly.

Try Dumbbells

Dumbbells allow your wrists to find their natural angle.

Limit Frequency

1-2x per week may be better than more frequent sessions.

Use Alternatives

If skull crushers always hurt, substitute with overhead cable extensions or French press.

Skull Crusher Variations

EZ Bar Skull Crusher

• Most common version
• Angled grip is elbow-friendly
• Recommended for most lifters

Dumbbell Skull Crusher

• One dumbbell in each hand
• Allows neutral grip (easier on joints)
• Can also use a single dumbbell held with both hands

Cable Skull Crusher

• Lying position with rope or bar attachment
• Constant tension throughout
• Very joint-friendly

Incline Skull Crusher

• On an incline bench
• Increased long head stretch
• Harder than flat

Decline Skull Crusher

• On a decline bench
• Different angle, some prefer the feel
• Less common

Single-Arm Skull Crusher

• One arm at a time with dumbbell
• Addresses imbalances
• Requires more stabilization

Programming Skull Crushers

For Tricep Mass

• Frequency: 1-2x per week
• Sets × Reps: 3-4 × 8-12
• When: After compound pressing or on arm day
• Rest: 90-120 seconds

In a Push Day (PPL)

1. Bench press: 4×6
2. Overhead press: 3×8
3. Incline dumbbell press: 3×10
4. Skull crushers: 3×10
5. Lateral raises: 3×15
6. Tricep pushdowns: 2×15

In an Arm Day

Triceps:

1. Close-grip bench: 3×8
2. Skull crushers: 4×10
3. Tricep pushdowns: 3×12
4. Overhead extension: 2×15

Biceps: (Followed by bicep work)

Superset Option

• Skull crushers × 10
• Close-grip press × 10 (same weight, no rest)
• Brutal tricep combination

How Heavy Should You Go?

Skull crushers work well with moderate weight:

Guidelines

• 8-10 reps: Moderate-heavy, strength focus
• 10-12 reps: Standard hypertrophy range
• 12-15 reps: Lighter, joint-friendly option

Signs You're Too Heavy

• Upper arms move excessively
• Can't control the descent
• Elbow pain
• Cutting range of motion short

Tips for Better Skull Crushers

1. Use an EZ Bar

More comfortable for most people's wrists and elbows.

2. Lower Behind Your Head

Better tricep stretch and long head activation.

3. Keep Elbows Pointed Up

Don't let them flare out to the sides.

4. Control the Weight

Slow and controlled beats fast and heavy.

5. Full Range of Motion

Deep stretch at bottom, full lockout at top.

6. Progress Gradually

Add weight slowly; elbows don't like sudden jumps in load.

Sample Tricep Workouts with Skull Crushers

Mass Focus

1. Close-grip bench press: 4×6
2. Skull crushers: 4×10
3. Overhead cable extension: 3×12
4. Tricep pushdowns: 3×15

Arm Day Classic

1. Skull crushers: 4×10
2. Tricep pushdowns: 3×12
3. Overhead dumbbell extension: 3×12
4. Barbell curls: 4×10
5. Hammer curls: 3×12
6. Concentration curls: 2×12

Quick Tricep Blast

1. Skull crushers: 3×12
2. Pushdowns: 3×12
3. Dips or close-grip push-ups: 2× max

The Bottom Line

Skull crushers are one of the best exercises for tricep mass because they:

• Target the long head (largest tricep head)
• Allow progressive overload with decent weight
• Provide a deep stretch under load

Key points:

1. Lower the bar behind your head for better stretch
2. Keep elbows pointed up, upper arms stationary
3. Use a weight you can control through full ROM
4. EZ bar is easier on joints than straight bar
5. If elbows hurt, try variations or alternatives

Include skull crushers in your arm training for complete tricep development. Combined with pushdowns, they cover all bases for building bigger, stronger triceps.