Upper Arms Exercise · Barbell

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Barbell Lying Triceps Extension

Also known as: Skull Crusher, Lying Tricep Extension, Skullcrusher

Category

Upper Arms

Equipment

Barbell

Target

Triceps

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Biomechanical cues verified by the PlanWorkouts Science Review Board under CSCS editorial oversight; see our editorial standards.

The barbell lying triceps extension is the umbrella version of the skull crusher pattern — bar lowered to the head from a flat bench, isolating the triceps through a long range. It's one of the more reliable triceps mass builders precisely because the joint only moves at the elbow. Keep a slight tuck in the elbows rather than letting them splay wide, which protects against unwanted shoulder involvement.

How to Do the Barbell Lying Triceps Extension

1. Lie flat on a bench, feet planted on the floor, with your head positioned at the end of the bench.
2. Grip the barbell overhand with your hands shoulder-width apart, and extend your arms straight up above your chest.
3. Keeping your upper arms fixed in place, slowly bend your elbows to bring the barbell down toward your forehead.
4. Pause briefly at the bottom, then extend your arms to return to the starting position.
5. Execute the desired number of reps with smooth cadence and consistent focus on the triceps.

Biomechanical & Joint Load Cues

Single-joint elbow extension isolating the triceps brachii (lateral, medial, and long heads). Keep upper arm fixed to prevent shoulder momentum.

Common Mechanical Mistakes & Form Errors to Avoid

• Flaring Elbows Outward: Allowing elbows to wing outward during pushdowns or extensions shifts tension to the chest and shoulders while stressing elbow ligaments.
• Moving the Upper Arms: Swinging the humerus back and forth turns the movement into a lat pullover rather than isolated elbow extension.
• Incomplete Lockout Extension: Stopping short of full arm extension prevents full recruitment of the triceps medial and lateral heads.

Proper Breathing Patterns & Core Engagement

Inhale as elbow flexes to full stretch; exhale as forearm extends straight.

Injury Modification & Joint Safety

Individuals with triceps tendon irritation at the elbow should avoid excessive deep elbow flexion (>90°) on skull crushers and prefer cable pressdowns. If joint irritation persists, immediately stop and substitute this movement with another exercise from the Upper Arms exercises category.

Muscles Worked

The Barbell Lying Triceps Extension primarily targets the Triceps, with Shoulders as the primary synergist muscle group.

More Upper Arms Exercises

Assisted Standing Triceps Extension (with Towel) Assisted · Triceps Assisted Triceps Dip (kneeling) Leverage Machine · Triceps Band Alternating Biceps Curl Band · Biceps Band Close-Grip Push-Up Band · Triceps Band Concentration Curl Band · Biceps Band One Arm Overhead Biceps Curl Band · Biceps

More Triceps Exercises

Band Side Triceps Extension Band · Triceps Barbell Close-Grip Bench Press Barbell · Triceps Barbell Decline Close Grip To Skull Press Barbell · Triceps Barbell Incline Close Grip Bench Press Barbell · Triceps Barbell Incline Reverse-Grip Press Barbell · Triceps Barbell Jm Bench Press Barbell · Triceps

Equipment Alternatives

Don't have barbell? These target the same triceps with different equipment.

Bench Dip (knees Bent) Body Weight · Triceps Band Side Triceps Extension Band · Triceps Cable Alternate Triceps Extension Cable · Triceps Dumbbell Close Grip Press Dumbbell · Triceps

FAQ

What muscles does the Barbell Lying Triceps Extension work?

The Barbell Lying Triceps Extension primarily targets the triceps as the primary agonist. The shoulders acts as the primary supporting muscle group during force transmission. Maintaining strict biomechanical alignment ensures maximal tension remains focused on the intended muscle fibers rather than shifting to surrounding stabilizer joints.

What equipment do I need for the Barbell Lying Triceps Extension?

The Barbell Lying Triceps Extension is performed using a barbell. Ensure all equipment is securely positioned with collars or safety pins locked before loading working sets. If you train in a home gym or minimal setup, explore our equipment-free and resistance band alternatives below.

What is the most common form mistake on the Barbell Lying Triceps Extension?

The most frequent error is flaring elbows outward: Allowing elbows to wing outward during pushdowns or extensions shifts tension to the chest and shoulders while stressing elbow ligaments.. Controlling the 2 to 3-second eccentric lowering phase ensures maximal hypertrophic stimulus while shielding connective tissue.

How many sets and reps should I perform on the Barbell Lying Triceps Extension?

For muscle growth and density, execute 3 to 4 working sets of 10 to 15 controlled repetitions with 60 seconds rest, emphasizing a deep stretch and deliberate peak contraction on every rep.

What's a good alternative to the Barbell Lying Triceps Extension?

If you don't have access to a barbell, the Bench Dip (knees Bent) targets the same triceps using body weight instead. This alternative replicates the same joint angle and movement plane while allowing you to train effectively with different available gear. You can also substitute it seamlessly in our free Workout Plan Builder.