Upper Arms Exercise · Barbell
Barbell Lying Extension
Also known as: Bb Lying Extension
- Category
- Upper Arms
- Equipment
- Barbell
- Target
- Triceps
Biomechanical cues verified by the PlanWorkouts Science Review Board under CSCS editorial oversight; see our editorial standards.
The Barbell Lying Extension is a targeted isolation upper arms movement designed to train the Triceps.
Single-joint elbow extension isolating the triceps brachii (lateral, medial, and long heads). Keep upper arm fixed to prevent shoulder momentum. Executing this with strict form maximizes muscle fiber recruitment while protecting joint structures.
Quick Exercise Facts
Target Muscle Activation
The barbell lying extension is the general triceps isolation movement most people know as a skull crusher, lowering the bar to the head or behind it while lying flat. The long range under tension is what makes it effective for triceps size, more so than heavier compound pressing where the triceps only work through part of the range. Keep the upper arms still and let the forearm do the moving.
How to Do the Barbell Lying Extension
- Lie on a bench with your feet flat on the floor and your head near the end of the bench.
- Grip the barbell overhand, hands shoulder-width apart, extending your arms straight up over your chest.
- With your upper arms held still, slowly bend your elbows to lower the barbell toward your forehead.
- Pause briefly, then straighten your arms back to the starting position.
- Perform for your targeted rep count, focusing on a deliberate tempo and maximum tension in the triceps.
Recommended Sets & Reps by Training Goal
65–75% 1RM · 60s rest
50–60% 1RM · 30–45s rest
Controlled 3s eccentric · 60s rest
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.
Add the Barbell Lying Extension to Your Custom Workout Routine
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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 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 Dip (kneeling)
Band Alternating Biceps Curl
Band Close-Grip Push-Up
Band Concentration Curl
Band One Arm Overhead Biceps Curl
More Triceps Exercises
Band Side Triceps Extension
Barbell Close-Grip Bench Press
Barbell Decline Close Grip To Skull Press
Barbell Incline Close Grip Bench Press
Barbell Incline Reverse-Grip Press
Barbell Jm Bench Press
Equipment Alternatives
Don't have barbell? These target the same triceps with different equipment.
Bench Dip (knees Bent)
Band Side Triceps Extension
Cable Alternate Triceps Extension
Dumbbell Close Grip Press
FAQ
- What muscles does the Barbell Lying Extension work?
- The Barbell Lying 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 Extension?
- The Barbell Lying 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 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 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 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.