Concentration curl

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How to do it

Seated, brace the elbow against your inner thigh to fully isolate the biceps. Curl without moving the upper arm and squeeze at the top; the brace removes all momentum.

Muscles worked

Mainly biceps. Train it inside a balanced routine to progress safely.

Recommended sets and reps

As an isolation exercise, it works best in 3–4 sets of 10–15 reps with 0–2 RIR. Use it at the end of the session to add volume without systemic fatigue.

Common mistakes to avoid

• Swinging the body and letting the elbows drift forward, turning the curl into a shoulder movement.
• Using too much weight at the cost of technique and full range of motion.
• Doing reps too fast, without controlling the eccentric (lowering) phase.

The blind spot of the concentration curl: where it trains and where it does not

The dumbbell concentration curl has a reputation as the biceps-peak exercise, and that reputation comes from a real sensation: with the elbow braced against the thigh there is no way to swing or help with the back, so the biceps works isolated and the contraction at the top is felt as in few other exercises. All of that is true. What almost never gets told is the other half.

With the elbow braced on the inner thigh, the arm sits in front of the torso. The biceps crosses two joints — elbow and shoulder — and in that position, with the shoulder somewhat flexed, part of its range is already shortened before the first repetition begins. In other words: the concentration curl loads the final part of the movement very well and the initial part, the long-muscle one, considerably worse.

Why that can matter was measured by a study with a design that is hard to argue with. Pedrosa, Simões, Figueiredo and colleagues, with Schoenfeld among the authors, published a study in Sports in 2023 with nineteen young women in which each arm of the same person trained in a different range of the seated preacher curl: one in the initial range (0° to 68° of elbow extension) and the other in the final range (68° to 135°), three times a week for eight weeks.

The initial range — the long-muscle one — produced a greater increase in cross-sectional area at the distal biceps, at 70% of upper arm length, and also greater 1RM gains. At 50% of arm length both ranges grew similarly.

That study did not compare the concentration curl against other curls, so it does not say the concentration curl is worse: it says the stretch of the range you train in changes the outcome. The application is direct and requires giving nothing up: use the concentration curl for what it does well — isolating without cheating and loading the contraction — and pair it with a curl that loads the stretch, with the arm behind the body. The incline dumbbell curl and the Bayesian cable curl exist precisely for that stretch.

Two arms, two stretches of the range, one complete biceps. Rather more useful than arguing about whether the biceps peak can be trained.

Alternative exercises

• Barbell curl
• Alternating dumbbell curl
• Hammer curl
• Preacher curl
• Low cable curl

More Isolation exercises

• Band concentration curl
• Resistance band biceps curl
• Preacher curl
• Overhead cable curl
• Low cable curl

Add it to your routine

Progrevia can generate a personalized routine that includes Concentration curl based on your level, goal and available days.

Frequently asked questions

What muscles does Concentration curl work?

Concentration curl mainly works the biceps muscle group, plus synergist and stabilizer muscles depending on the variation.

How many sets of Concentration curl should I do?

Between 3 and 5 sets per session, adjusting the total weekly volume for biceps to your level (about 10–20 sets per muscle per week).

Is Concentration curl good for building muscle?

Yes. Combined with progressive overload, good technique and enough rest, it's an effective tool to grow biceps.

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