How to Do the Concentration Curl

How to do it

1. Sit on a flat bench with your feet spread wider than shoulder-width and planted firmly on the floor, leaning your torso forward slightly so your upper body is inclined over your thighs.
2. Pick up a dumbbell in one hand and rest the back of that upper arm (the triceps side) firmly against your inner thigh, just above the knee, so the arm hangs straight down with the dumbbell cleared from the floor.
3. Place your free hand on the opposite knee or thigh to stabilize your torso and prevent any rotation during the set.
4. Before initiating the rep, let your elbow fully extend so the biceps are under a real stretch at the bottom, and make sure your wrist is neutral or very slightly supinated.
5. Curl the dumbbell upward in a smooth arc by contracting the biceps, keeping the back of your upper arm pressed into your thigh throughout the entire movement so the elbow acts as a fixed pivot.
6. At the top, squeeze hard for a full count when the dumbbell is near shoulder height and you feel the biceps at maximum contraction. The dumbbell should NOT touch your shoulder or arm.
7. Lower the weight under control over about two to three seconds back to full elbow extension. Do not let the dumbbell drop or bounce off the thigh at the bottom.
8. Complete all reps on one arm before switching sides, keeping the rest of your body still throughout the set.

Form cues

• Elbow stays pinned to the thigh the whole rep.
• Full stretch at the bottom, every rep.
• Squeeze and hold at the top for a beat.
• Wrist stays neutral, don't let it curl or crank.
• Torso quiet. If you're rocking, the weight is too heavy.

Common mistakes

• Letting the elbow drift away from the thigh: as soon as the upper arm loses contact with the inner thigh, the anterior deltoid starts assisting and the isolation effect disappears. Consciously press the arm into the leg before and during every rep.
• Cutting the range of motion short at the bottom: starting each rep without reaching full elbow extension means the biceps never get a proper stretch, which shortens the effective range and reduces the training stimulus. Let the arm hang fully straight before curling.
• Using too much weight and compensating with torso swing: the whole point of the concentration curl is that the thigh locks the arm in place. If you're heaving your torso or raising your shoulder to get the weight up, reduce the load immediately.
• Rushing the eccentric: lowering the dumbbell in under a second wastes half the set. The biceps are often stronger eccentrically than concentrically, and a controlled lower of two to three seconds significantly increases the total work done.
• Letting the wrist hyperextend or curl: a bent wrist shifts stress toward the forearm flexors and can aggravate the wrist joint over time. Keep the wrist locked in a neutral position as though you're holding a hammer.

Why do the Concentration Curl?

• Because the upper arm is mechanically fixed against the thigh, there is virtually no way to cheat the rep with momentum, making it one of the most honest tests of pure biceps strength in a dumbbell-only context.
• The position places the long head of the biceps in a slightly shortened state and the short head in a favorable line of pull, which many lifters find produces a stronger mind-muscle connection and a more pronounced peak contraction than standing curls.
• Working one arm at a time naturally exposes and helps address strength imbalances between sides, since you cannot compensate by having the dominant arm take over as you can with a barbell.
• As a single-joint isolation exercise with no stabilizer confusion, concentration curls are commonly used in rehabilitation and prehab contexts to rebuild biceps strength after elbow or shoulder issues without loading the shoulder complex heavily.
• The seated, braced position is extremely low-fatigue systemically, so it can fit at the end of a session after heavy compound work without compromising recovery or technique.

Concentration Curl variations

Cable Concentration Curl

Attaching a low cable to a D-handle and mimicking the seated concentration curl position provides constant tension through the entire arc, including at the bottom where a dumbbell goes slack, making it a useful progression when you want more stimulus at the stretched position.

Incline Dumbbell Concentration Curl

Performing the curl seated on an incline bench and letting the arm hang off the side places the biceps under a longer stretch at the bottom, which can be a useful variation for lifters chasing hypertrophy who want to emphasize the lengthened portion of the range.

Standing Concentration Curl

Bending at the hips and bracing the working arm against the inner thigh while standing requires more core and hip stability, making it a slight regression in terms of isolation but a good option when no bench is available.

Slow-Tempo Concentration Curl

Using the same dumbbell but applying a four-second eccentric and a two-second pause at peak contraction dramatically increases time under tension without adding load, commonly used by lifters who have reached a plateau or are training around elbow discomfort.

How to program it

The concentration curl tends to appear at the end of an upper body or arm-focused session, after compound pulling movements like rows or pull-ups have already fatigued the biceps broadly. Most lifters program it in the 8 to 15 rep range, prioritizing a controlled tempo and peak contraction over moving heavy loads. Because it requires minimal setup and produces very little systemic fatigue, it is also common to see it used as a superset finisher paired with a triceps exercise. Some bodybuilding programs place it in higher-rep ranges of 12 to 20 to chase a pump at the end of a session, while strength-focused lifters sometimes use it in the 6 to 10 range to address a specific side's lagging output.

Concentration Curl alternatives

Barbell Curl

Barbell · Isolation

Cable Curl

Cable · Isolation

Preacher Curl

Barbell · Isolation

Dumbbell Curl

Dumbbell · Isolation

Hammer Curl

Dumbbell · Isolation

Incline Dumbbell Curl

Dumbbell · Isolation