Concentration Curl
The highest-isolation biceps movement — no way to cheat it.
Setup
- Seated, elbow braced against the inside of the thigh, arm hanging straight.
- Feet planted wide, torso leaning slightly forward.
How To Do It
- Curl the bell to the shoulder without letting the elbow leave the thigh.
- Squeeze hard at the top.
- Lower all the way until the arm is straight.
Breathing
Exhale on the curl.
Common Mistakes
- Swinging the torso to start the rep.
- Cutting the bottom short and losing the stretch.
Programming It
Two to three sets of 10-15 per arm.
Why This Exercise Works
Bracing the elbow against the thigh removes every possible contribution from the shoulder and torso, so the biceps works alone through a full range. It is not a mass builder at these loads — it is how you find out whether one arm is genuinely weaker.
Where You Should Feel It
An isolated squeeze in the biceps with no help available from anywhere. The elbow pinned to the thigh removes every cheat. If the shoulder is working, the arm has come off the leg.
Where It Fits in a Program
The highest-isolation biceps movement — no way to cheat it. Save it for the back half of a session, where fatigue costs you little.
Progressing and Regressing It
To progress the concentration curl: add a small increment, matching both arms. To regress it: reduce the load until the elbow stays pinned to the thigh.
Who It's For
Anyone chasing a peak, and anyone who wants to fix a side-to-side arm difference. It is a finisher, not a strength exercise.
Equipment and Substitutions
What you need for this one: a dumbbell and a bench. Kettlebells substitute directly here. So does a cable, if you would rather have constant tension than a free weight.
Related Exercises
- Incline Dumbbell Curl — Biceps
- Scott Curl — Biceps
- Spider Curl — Biceps
- Cable Curl — Biceps
- Barbell Curl — Biceps
- Band Curl — Biceps
- Hammer Curl — Biceps, Forearms
- Preacher Curl — Biceps
Common Questions
What muscles does the concentration curl work?
The concentration curl primarily trains the biceps.
How many sets and reps should I do?
Two to three sets of 10-15 per arm.
What are the most common concentration curl mistakes?
Most often: swinging the torso to start the rep; cutting the bottom short and losing the stretch.
Do I need a dumbbell and a bench to do this?
This version uses a dumbbell and a bench, and it trains the biceps. Any hand-held load will do — kettlebell, plate, or a filled bag. The related list below covers the machine versions.
Is this safe if I have an existing injury?
Elbows and wrists take the brunt of the concentration curl, and both are slow to settle once irritated. If the ache lingers into the next day, reduce the load or change the grip angle before you train it again. Not medical advice.