Incline Dumbbell Curl Vs. Preacher Curl: Which is More Effective?

There are many variations of the bicep curl which are excellent for building bigger and more impressive guns. But today, we focus on the incline vs preacher dumbbell curl… two very popular exercises that are similar, yet different in many ways.

And both are beneficial for adding mass and strength if included in your bicep routine. But since we’re comparing the two, one has to be superior right?…

Well, let’s have a comparison and maybe, just maybe… we’ll have a verdict…

Biceps Anatomy

To have a better idea of how the biceps function according to how it is attached, let’s go over some biceps anatomy basics.

The biceps brachii has two heads which are the long (outer) head and the short (inner) head.

These muscles cross the shoulder and forearm. Therefore, both are responsible for flexion at the two ends. Although, forearm flexion is the more prominent action in which the biceps function.

And the biceps also functions to supinate the forearm.

Also, the long head assists in abduction (away from the midline of the body) of the arm, while the short head facilitates adduction (toward the midline of the body) of the arm.

Comparison

Incline Dumbbell Curl

The incline curl is performed with the torso at an inclined angle and the arms perpendicular to the ground and behind the body.

Pros

The incline curl elicits a similar pattern of neuromuscular activity throughout the entire range of motion due to the vertical arm angle.
The exercise position decreases the temptation and/or ease of cheating during the reps.

Cons

Not a good exercise for people with shoulder issues due to the strain of the arm position.

Dumbbell Preacher Curl

The preacher curl is performed with a slightly forward torso, and the upper arms are positioned at an inclined angle in front of the body resting against the padding.

Pros

Maximizes stretch and activation of the long head of the biceps (although, only during the initial concentric phase of the curl).

Cons

Only maximally effective during the initial concentric phase due to the inclined arm angle where the elbow is slightly bent and the load is maximally placed on the lower bicep.
Easier to cheat your reps, therefore, taking even more of the load off of the biceps.
Higher chance of tearing a bicep compared to a standard curl due to the load placed on the muscle at the forearm end.

Research Comparing Both Bicep Exercises

Study #1

The incline and preacher curl were both used as part of one ACE-sponsored study which compared the effectiveness of several bicep exercises for muscle activation by utilizing electromyographic (EMG) testing. (1)

And the incline curl only showed a small advantage over the preacher curl for muscle activation as a result of EMG testing. So, the difference was not significant and both elicited a very similar amount of muscle activation.

Although, all variables were not discussed.

Study #2

Another piece of scientific literature showed there to be maximum activation of the long head during the dumbbell preacher curl only when the elbow joint angle is close to full extension, and also when the elbow joint range of motion is shorter. (2)

This is because the biceps have to overcome a significant load torque during the initial concentric (positive) phase of the curl.

But, the neuromuscular demand then decreases rather quickly during the middle and final phase of the repetition shifting the force production from the elbow flexors to the extensors.

And this is due to the flexed shoulder position during the preacher curl which limits the stretch and activation of the long head past the initial concentric part of the curl, along with the inefficient length of the elbow flexors.

On the other hand, the incline curl showed similar activation of the biceps brachii for the entire range of motion due to the more ideal arm angle.

And the incline curl also showed up to 95% muscle activity during the final part of the concentric phase, whereas the preacher curl showed 80% during the initial portion of a rep.

The Verdict?

We definitely can’t ignore the differences between these two very popular bicep exercises.

…So, which is more effective?

Well, based on the studies we found which compared the two, the incline curl is the clear winner here.

But even regardless of the studies, we can tell where the load is placed on each muscle based on the arm position during each exercise.

The vertical position of the arms during the incline curl keeps a constant tension and stretch on the biceps. Whereas the preacher curl only allows a stretch and maximum tension during the first part of the curl.

Therefore, the incline dumbbell curl is the overall better exercise when training to improve biceps force and hypertrophy.

But does that mean we should ignore the preacher curl? Not at all.

In fact, the muscle activity of the long head during near extension of the elbow during the preacher curl is even more than the nearly fully extended position of the incline dumbbell curl.

But, overall, muscle activity was higher for the incline curl during the last part of the concentric phase, than it was for the preacher curl during the beginning of the concentric phase.

So, we believe we have an answer for those wondering which is better overall. But you can still use both for the benefits each has to offer. However, only if you’re executing each exercise correctly.

Important Exercise Tips

To ensure you perform each exercise safely and correctly, there are a few things to keep in mind.

Incline curl

Avoid the incline curl if you have shoulder issues as the angle can place a dangerous strain on the joint. This is where a neutral position or even a preacher style curl is superior.
Another option is to adjust the bench to where it’s only at a slight incline which will minimize stress on the shoulders.

Preacher curl

Avoid full extension of the elbow during the preacher curl to keep tension on the biceps and to prevent a bicep tear due to the excessive load placed on the lower bicep.
Lean forward into the bench during the preacher curl to ensure optimum tension on the bicep through the curl.
Avoid leaning back during the preacher curl to prevent taking the tension away from the biceps muscles.

We hope you find these training tips helpful for your training progress, and you can use both exercises for the advantages each has to offer.