Concentration Curl: how to do it right
In short: The concentration curl isolates the biceps with a peak of tension in the shortened position, elbow bent and arm locked against the thigh.
How to do it, step by step
- 1Seated, torso leaning forward, brace the back of your arm (triceps) against the inside of your thigh, elbow firmly fixed.
- 2Arm almost straight at the bottom, palm facing inward, curl the dumbbell up by bending only the elbow.
- 3At the top, supinate slightly and squeeze the biceps hard for 1 second, with the elbow staying on your thigh.
- 4Control the return over 2 to 3 seconds without losing tension.
- 5Keep your torso steady: no swinging, the elbow works alone.
The mistake to avoid
Don't swing your torso to help raise the dumbbell.
Other common mistakes
- Swinging the torso to throw the dumbbell up: fix the arm and go lighter if you cheat.
- Not pausing at the top: hold the contraction for 1 second, that's the whole point of the movement.
- Lifting the elbow off the thigh: keep it braced to truly isolate the biceps.
- Returning too fast and losing tension: slow it down over 2 to 3 seconds.
Muscles worked
- Main:
- Biceps
The biceps brachii is the prime mover, with an emphasis on its short head given the flexed shoulder and the elbow in front of the trunk. The brachialis (under the biceps) backs up the flexion, and the brachioradialis stabilizes the forearm. No notable secondary muscle: bracing on the thigh eliminates cheating.
What to replace it with
Same muscle, same part of the movement: these exercises do the same job.
Frequently asked questions
How do I do this exercise?
Seated, torso leaning forward, brace the back of your arm (triceps) against the inside of your thigh, elbow firmly fixed. Arm almost straight at the bottom, palm facing inward, curl the dumbbell up by bending only the elbow. At the top, supinate slightly and squeeze the biceps for 1 second, then control the return without swinging your torso.
How far do I go up and down?
Go up to a full contraction, forearm folded in, and squeeze hard for 1 second at the top: that's where the peak tension hits on this movement. At the bottom, straighten the arm almost fully but keep the tension, don't relax. Use the range you can control without squirming.
I don't feel anything, is that normal?
You should feel the biceps, especially during the squeeze at the top. If you feel nothing, go lighter and focus on the 1-second squeeze and the slow return. Visualize the biceps shortening, with the elbow firmly braced against the thigh. Sensation matters more than weight.
How fast should I do the movement?
Curl up firmly, squeeze for 1 second at the top, then slow the return over 2 to 3 seconds without losing tension. The squeeze at the top and the slow return do all the work here, not speed.
How do I breathe?
Breathe in at the bottom, breathe out on the way up and during the squeeze at the top. Keep a light brace to stabilize your leaning torso, but the effort stays local to the arm.