What is a concentration curl?

A concentration curl is a seated single-arm dumbbell curl where the back of the upper arm is braced against the inner thigh. This physical anchor eliminates upper-body momentum and isolates elbow flexion.

What muscles do concentration curls target?

Concentration curls primarily target the biceps brachii, with particular emphasis on the short (inner) head due to the forward arm position and full supination. The brachialis and brachioradialis act as supporting elbow flexors.

Where should your elbow be placed during concentration curls?

Place the flat lower portion of your tricep against the inside of your inner thigh, just above the knee. Never place the point of the elbow directly on top of the knee or thigh bone.

Are concentration curls better than standard standing curls?

Concentration curls are not universally better, but EMG studies show exceptionally high biceps activation because torso swinging is mechanically restricted. They are best used as an isolation accessory alongside heavier compound or standing lifts.

When should I stop a set of concentration curls?

End the set as soon as you cannot reach full contraction without leaning your torso backward, when your elbow lifts off your inner thigh, or when you can no longer lower the weight under control.

Concentration Curl: Form, Seated Setup and Mistakes

Concentration Curl

Master concentration curl form with seated inner-thigh elbow brace cues, wrist alignment, biceps short-head isolation, and set termination rules.

Quick answer: Sit on a flat bench with feet wide, brace the back of your working tricep against your inner thigh, curl the dumbbell upward without shifting your shoulder or torso, and stop when body sway or elbow drift occurs.

Dumbbells and flat bench beginner Biceps

How to Do It

Sit on the edge of a flat bench with your legs spread comfortably wider than shoulder-width and feet flat on the floor.

Grip a dumbbell with one hand and brace the lower back of your tricep against the inside of your same-side inner thigh.

Let your arm hang straight down with your palm facing forward or slightly inward, ensuring the elbow stays firmly against the thigh.

Curl the dumbbell upward toward your shoulder by bending only at the elbow, keeping your upper body completely stationary.

Squeeze your bicep firmly at the top of the range of motion for a brief pause without rolling your shoulder forward.

Lower the dumbbell under steady control back to full extension before beginning the next repetition.

Common Mistakes

Resting the point of the elbow on top of the thigh instead of bracing the back of the tricep against the inner thigh.

Swinging the torso backward or using shoulder momentum to initiate the upward curl.

Allowing the wrist to curl excessively upward or collapse backward under load.

Cutting the bottom range short instead of allowing full elbow extension.

Letting the working shoulder drop or hunch forward during the contraction.

The concentration curl is a classic unilateral biceps exercise designed to maximize elbow flexion isolation by eliminating torso swing. By anchoring the back of your working arm against your inner thigh, you create a rigid mechanical barrier that prevents momentum, forcing the biceps brachii to perform the entire workload.

Seated Setup & Arm Anchor Matrix

Proper execution depends on where and how your arm is anchored against your leg.

Setup Component	Proper Placement	Common Error	Correction
Bench Position	Edge of flat bench, torso inclined ~45°	Sitting too far back	Slide forward to allow full arm hang
Foot Stance	Wide stance, feet flat on floor	Narrow feet crowding arm	Widen feet so elbow clears opposite knee
Arm Anchor	Flat tricep against inner thigh	Olecranon (elbow point) on knee	Drop contact point 2 inches below thigh crest
Non-Working Hand	Braced on opposite knee for stability	Hanging loosely	Firmly grip opposite knee to lock torso

Step-by-Step Execution Guide

Establish the Stable Base: Sit on the edge of a flat bench with your feet planted wider than shoulder-width. Hold a dumbbell with an underhand (supinated) grip in your right hand.
Anchor the Tricep: Lean forward from the hips and press the lower tricep of your right arm against the inside of your right thigh. Place your left hand firmly on your left knee to stabilize your spine.
Hang to Full Extension: Allow the dumbbell to hang straight down toward the floor between your legs. Ensure your arm is fully extended without over-stretching the elbow joint.
Initiate Strict Flexion: Without moving your torso or shoulder, contract your right bicep to curl the dumbbell up toward your chest. Keep your wrist neutral.
Peak Contraction: Squeeze your bicep hard at the top of the movement for a 1-second pause. Ensure your elbow remains anchored to your inner thigh.
Controlled Eccentric: Lower the dumbbell under control along the same path over 2 to 3 seconds until your arm reaches full extension. Complete all prescribed repetitions before switching arms.

Programming & Quality Stop Rules

Concentration curls function best as a secondary or tertiary movement on pull or arm days.

Hypertrophy Focus: 3 sets of 10–12 repetitions with a 2-second lowering phase.[1][2]
Form Failure Boundary: Terminate the set immediately if your torso rocks backward to yank the weight up, or if your elbow slips off the inner thigh during the concentric phase.[1][2]

References

National Strength and Conditioning Association. Anaerobic and Muscle Endurance Development: Lifting Guidelines. National Strength and Conditioning Association (2017)Back to claim
Brad S Currier, Alysha C D'Souza, Maria A Fiatarone Singh, Caroline V Lowisz, Eric S Rawson, Brad J Schoenfeld, Abbie E Smith-Ryan, Jeremy P Steen, Gwendolyn A Thomas, N Travis Triplett, Tyrone A Washington, Timothy J Werner, Stuart M Phillips. American College of Sports Medicine Position Stand. Resistance Training Prescription for Muscle Function, Hypertrophy, and Physical Performance in Healthy Adults: An Overview of Reviews. Medicine & Science in Sports & Exercise (2026)Back to claim
Deborah Riebe, Barry A Franklin, Paul D Thompson, Carol E Garber, George P Whitfield, Melissa Magal, Linda S Pescatello. Updating ACSM's Recommendations for Exercise Preparticipation Health Screening. Medicine & Science in Sports & Exercise (2015)

See our exercise methodology for how this evidence is applied and its limits.

Frequently Asked Questions

What is a concentration curl?: A concentration curl is a seated single-arm dumbbell curl where the back of the upper arm is braced against the inner thigh. This physical anchor eliminates upper-body momentum and isolates elbow flexion.
What muscles do concentration curls target?: Concentration curls primarily target the biceps brachii, with particular emphasis on the short (inner) head due to the forward arm position and full supination. The brachialis and brachioradialis act as supporting elbow flexors.
Where should your elbow be placed during concentration curls?: Place the flat lower portion of your tricep against the inside of your inner thigh, just above the knee. Never place the point of the elbow directly on top of the knee or thigh bone.
Are concentration curls better than standard standing curls?: Concentration curls are not universally better, but EMG studies show exceptionally high biceps activation because torso swinging is mechanically restricted. They are best used as an isolation accessory alongside heavier compound or standing lifts.
When should I stop a set of concentration curls?: End the set as soon as you cannot reach full contraction without leaning your torso backward, when your elbow lifts off your inner thigh, or when you can no longer lower the weight under control.