Lying Barbell Tricep Extension (Skull Crusher)
The Lying Barbell Tricep Extension is a classic strength exercise that focuses on isolating and loading the triceps through controlled elbow extension.
Lying Barbell Tricep Extension (Skull Crusher)
Muscles Worked: Lying Barbell Tricep Extension (Skull Crusher)
The lying barbell tricep extension mainly trains your arms, with the triceps doing almost all of the work. Your triceps straighten your elbows to move the bar from near your forehead to over your chest, and they stay under tension because your upper arms hold position through the set. This makes it a true isolation lift for the back of your upper arm, not a chest or shoulder press. If your elbows stay fairly still, you should feel the triceps doing the work from stretch to lockout, and research suggests triceps growth can differ based on arm position during elbow extension work (Maeo et al., 2023).
Technique and form
How to perform the Lying Barbell Tricep Extension (Skull Crusher)
- Lie flat on a bench with your feet planted firmly on the floor and grip the barbell with hands positioned shoulder-width apart using an overhand grip.
- Extend your arms straight above your chest with the barbell directly over your shoulders, keeping your wrists straight and elbows locked.
- Inhale as you slowly bend your elbows to lower the barbell toward your forehead, keeping your upper arms stationary and perpendicular to the floor.
- Maintain control of the weight throughout the descent, ensuring your elbows remain pointed toward the ceiling and don't flare outward.
- Lower the barbell until it nearly touches your forehead or the area just behind it, creating a 90-degree angle at your elbows.
- Exhale as you extend your elbows to push the barbell back up to the starting position, focusing on contracting your triceps.
- Keep your upper arms stable throughout the movement, ensuring all the work comes from your elbow extension rather than shoulder movement.
- Repeat for the prescribed number of repetitions, maintaining a controlled tempo and avoiding any jerking or momentum-based movements.
Important information
- Keep your elbows tucked in throughout the exercise to maximize tricep engagement and reduce strain on your shoulders.
- Choose an appropriate weight that allows you to maintain proper form; using too heavy a load may cause your elbows to flare out or your form to break down.
- Make sure your bench is stable and your upper back remains firmly planted on the bench throughout the entire movement.
- If you experience any elbow pain, consider using an EZ curl bar instead of a straight barbell as it places your wrists in a more neutral position.
Is the Lying Barbell Tricep Extension (Skull Crusher) good for muscle growth?
Yes. The lying barbell tricep extension is a strong muscle-building exercise for the triceps because it lets you load elbow extension directly without your chest or shoulders taking over. Research on triceps training shows that arm position can affect hypertrophy outcomes during elbow extension work, with overhead positions producing greater triceps growth than neutral positions in one study (Maeo et al., 2023).
- Direct triceps tension — This lift keeps the focus on straightening the elbow, which is the triceps' main job. That makes it easier to give the triceps hard, high-quality work without the set being limited by bigger muscle groups.
- Strong stretch at the bottom — Lowering the bar toward your forehead or slightly behind it can put the triceps under a deep stretch, especially the long head. That matters because overhead elbow extension work has produced more triceps growth than neutral arm positions in research, supporting the idea that arm position and muscle length can influence the training effect (Maeo et al., 2023).
- Easy to pair with presses — Skull crushers fit well after close-grip or pressing work because they add targeted triceps volume once heavier compound sets are done. Exercise order can affect resistance training adaptations, and this supports organizing single-joint work after big lifts when that fits your training priorities (Brandão et al., 2020).
- Simple progression options — You can progress by adding small amounts of weight, adding reps, or improving range of motion while keeping your elbows in place. If a straight bar bothers your wrists or elbows, the ez-bar-lying-triceps-extension is often a smoother variation, and dumbbell-lying-triceps-extension can help even out side-to-side differences.
Programming for muscle growth
Do 3-4 sets of 8-12 reps with 60-90 seconds rest, 1-2 times per week. Use a weight you can lower slowly and control at the bottom, because losing elbow position usually turns the set into a sloppy press. Put skull crushers after your main pressing work so your elbows are warm and your heavier compound lifts do not suffer.
Lying Barbell Tricep Extension (Skull Crusher) Variations
Alternative Exercises
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FAQ - Lying Barbell Tricep Extension (Skull Crusher)
Skull Crushers primarily target all three heads of the triceps brachii, with particular emphasis on the long head. The exercise also engages the shoulders and chest as stabilizers, but the triceps perform the majority of the work throughout the movement.
To prevent elbow pain, avoid locking out your elbows at the top of the movement, use a weight you can control with proper form, and consider using an EZ-curl bar instead of a straight barbell. Warming up your elbows properly and ensuring your arms remain perpendicular to the floor throughout the exercise will also reduce strain.
Include Skull Crushers 1-2 times per week with at least 48 hours between sessions to allow for proper triceps recovery. They work well as part of an upper body or push day, typically performing 3-4 sets of 8-12 repetitions for hypertrophy goals.
The most common mistakes include flaring the elbows outward (keep them pointing toward the ceiling), allowing the upper arms to drift backward (maintain a perpendicular position to the floor), and using momentum by lifting the head or shoulders off the bench. Using excessive weight that compromises your form is also a frequent error.
While classified as an intermediate exercise, beginners can perform Skull Crushers by starting with very light weights or even an empty EZ-curl bar to master proper form. Consider having a spotter present and focus on controlled movement patterns before progressively adding weight as your triceps strength and coordination improve.
Workouts with Lying Barbell Tricep Extension (Skull Crusher)
Scientific References
Maeo S, Wu Y, Huang M et al. · European journal of sport science (2023)
Brandão L, de Salles Painelli V, Lasevicius T et al. · Journal of strength and conditioning research (2020)
Sources are peer-reviewed academic publications from PubMed.
Lying Barbell Tricep Extension (Skull Crusher)
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