Single-Arm Dumbbell Skullcrusher 101 Video Tutorial
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Exercise Synopsis
Target Muscle Group
Triceps
Execution
Isolation
Force Type
Pull
Required Equipment
Dumbbell
Fitness Level
Intermediate
Alternatives
Timer
Hour
Minute
Second
Stopwatch
00:00:00:00
Overview
The Single Arm Dumbbell Skullcrusher is an isolation exercise primarily targeting the triceps, helping to build strength and definition in the back of the upper arm. Performed lying on a bench or the floor, this movement involves lowering a single dumbbell behind the head using one arm, which emphasizes unilateral control and can help correct muscle imbalances between sides. While the triceps are the main focus, the exercise also engages stabilizing muscles in the chest and shoulders to maintain proper form and control throughout the movement. This makes it an effective option for developing arm strength and stability using minimal equipment.
How to Perform
Set up your position: Lie flat on a bench with your back fully supported and feet planted on the ground. Hold a dumbbell in one hand with a neutral grip (palm facing inward), and extend your arm straight up over your shoulder. Keep your other arm resting at your side or on your chest for stability.
Brace your core and align your arm: Engage your core muscles and keep your head, neck, and spine in a neutral position. Make sure your working arm is vertical and your elbow is directly above your shoulder.
Lower the dumbbell: Slowly bend your elbow to lower the dumbbell toward the side of your head or just behind it. Keep your upper arm as still as possible—only your forearm should move. Control the descent to avoid any sudden movement near your face.
Pause and feel the stretch: Once the dumbbell reaches its lowest point (just before it touches your shoulder or head), pause for a second. You should feel a deep stretch in your triceps.
Extend the arm back up: Push the dumbbell back to the starting position by straightening your elbow, focusing on contracting the triceps. Keep the motion slow and controlled to maximize muscle engagement.
Repeat and switch arms: Complete the desired number of reps, then switch to the other arm and repeat the same motion with equal form and control.
★ Bonus: For exercises that involve external weights (such as dumbbells, barbells, or machines), the One Rep Max (1RM) calculator can help you estimate your maximum lifting capacity. Use it to track your strength progress and adjust your training for optimal results.
Tips
Keep your elbow fixed in place to isolate the triceps effectively.
Avoid flaring your elbow out; keep it pointing straight up for better control.
Use a light to moderate weight to maintain strict form and avoid joint strain.
Perform the movement slowly, especially on the lowering phase, to increase time under tension.
Engage your core to prevent arching your lower back during the exercise.
Don’t allow the dumbbell to drift too far forward or backward—keep the motion vertical.
Keep your wrist straight and stable to avoid unnecessary strain.
Start with your non-dominant arm to ensure balanced development.
Use a spotter when lifting heavier weights near your head for safety.
Rest the non-working arm across your chest or stomach to avoid compensatory movement.
How Not to Perform
Do not let your elbow move around – keep it locked in place to avoid shifting tension away from the triceps.
Do not drop the dumbbell too quickly – control the descent to prevent joint strain or hitting your head.
Do not flare your elbow outward – this reduces triceps activation and increases shoulder involvement.
Do not use too heavy a weight – this often leads to poor form and places stress on the elbow and shoulder joints.
Do not arch your back – keep your spine neutral to avoid unnecessary pressure on your lower back.
Do not swing or use momentum – the movement should be slow and isolated for proper muscle engagement.
Do not twist your wrist or let it bend back – keep your wrist in a neutral, straight position to avoid strain.
Do not rush your reps – rushing reduces time under tension, which is key for muscle growth.
Do not let the dumbbell drift behind your head – keep the motion aligned and vertical to stay focused on the triceps.
Do not ignore pain in the elbow or shoulder – discomfort might signal poor form or an underlying issue, so adjust or stop if needed.
Variations
Variations of fitness exercises refer to different ways of performing a specific exercise or movement to target various muscle groups, intensities, or goals. These variations aim to challenge the body differently, prevent plateaus, and cater to individuals with varying fitness levels.
Alternatives
Alternative exercises in fitness refer to different movements or activities that target similar muscle groups or serve the same training purpose as the primary exercise. These alternative exercises can be used as substitutes when the original exercise is unavailable or challenging to perform due to various reasons such as equipment limitations, injuries, or personal preferences.
