Upper Arms Exercise · Dumbbell

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Dumbbell Lying Single Extension

Also known as: Db Lying Single Extension, Dumbell Lying Single Extension

Category

Upper Arms

Equipment

Dumbbell

Target

Triceps

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

Extending one arm at a time from a lying position isolates the triceps fully on that side, without a second dumbbell moving in sync to share the rhythm. That single-arm focus makes it easier to control the elbow path and catch technique breakdown before it happens. It's a good option for building triceps symmetry between arms.

How to Do the Dumbbell Lying Single Extension

1. Lie back on a bench holding a dumbbell in one hand, arm fully extended above your chest.
2. Lower the dumbbell under control toward your forehead while keeping your upper arm still.
3. Hold briefly at the bottom, then straighten your arm back to the start.
4. Continue for the target number of reps, then switch arms.

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 Dumbbell Lying Single 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 dumbbell? These target the same triceps with different equipment.

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

FAQ

What muscles does the Dumbbell Lying Single Extension work?

The Dumbbell Lying Single 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 Dumbbell Lying Single Extension?

The Dumbbell Lying Single Extension is performed using a dumbbell. 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 Dumbbell Lying Single 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 Dumbbell Lying Single 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 Dumbbell Lying Single Extension?

If you don't have access to a dumbbell, 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.