Inner Biceps Curl: Benefits, Muscles Worked, and More

published by: Debbie Luna
Last Updated:
January 19, 2023

Although the biceps curl looks simple enough as it is just a single-joint movement, as with any isolation exercise, it has dozens of variations to stimulate better engagement of either of the two heads of the biceps muscle. The inner biceps curl is one of those exercises designed to target the short head of the biceps more.

The inner biceps curl works similarly to a wide-grip barbell curl but without the awkwardness of the wrist position that contributes to discomfort and instability. This exercise allows for more external shoulder rotation when performing the movement, resulting in better engagement of the biceps’ short head.

It is difficult to completely isolate only the short head of the biceps, just as this would be impossible with any other muscle group. Despite this, some workouts promote a more significant engagement of the short head, like the inner biceps curl. Grip width, hand orientation, shoulder rotation, shoulder flexion, and glenohumeral angle all affect the two heads of the biceps to varying degrees of muscular activation. 

The Biceps Brachii: Anatomy and Functions

The biceps is a muscle on the front of the upper arm. Its name, biceps brachii, is a Latin phrase that roughly translates to "two-headed arm muscle."

These two heads of the biceps are responsible for elbow flexion (which brings the forearm closer to the body) and supination (rotating the forearm so that the palms face upward). 

biceps anatomy

Both the short and long heads of the biceps start at different points on the scapula. Nevertheless, they join together to form one muscular belly throughout the upper arm, and then they taper and enter the same region on the front of the elbow.

The biceps is a powerful supinator of the forearm. According to research by Jarrett et al., the short head is considerably more effective as a supinator in both the neutral and pronated positions of the forearm. However, when the forearm is supinated, the long head can do supination with more efficacy.

The most critical role that the biceps play in bending and straightening the elbow is to serve as a stabilizing and supporting structure for the brachialis muscle, which is located below the biceps. However, the mechanical momentum of the brachialis is at a disadvantage compared to that of the biceps muscle when the arm is in the supinated and flexed positions.

It is a common misconception that the biceps is the strongest muscle in the upper arm and is mainly responsible for raising or lowering the forearm. However, this is not the case, the biceps are only somewhat effective as elbow flexors compared to the brachialis, particularly when supination is not involved.

What is an Inner Bicep Curl?

The inner bicep curl is an isolation exercise intended to target the short head of the biceps. However, we rarely see lifters perform this exercise in the gym, maybe because of the awkward and unflattering look of the movement. 

inner bicep curl

The exercise is performed with a dumbbell in each hand using a neutral grip, and with the shoulders externally rotated while standing, seated upright, or on an inclined bench. The forearms are at about a 60° angle from the sagittal plane. The weights are raised towards the shoulder while slowly supinating the forearm as it approaches the top of the movement.

How to Perform the Inner Biceps Curl

Assume a standing position with feet hip-width apart while holding a dumbbell in each hand out to the side with an underhand grip. It is vital to keep the elbows close to the body. Next, rotate the shoulders externally and keep it that way for the rest of the routine. This will become the starting position.

inner bicep curl muscles

Curl the weights towards the shoulder while keeping the upper arms still and the elbows close to the body. At the top of the movement, hold for a second and give the biceps a squeeze. While drawing a deep breath, slowly return the dumbbells to the starting position. Maintain the shoulders' external rotation throughout the routine. Repeat the action for the desired number of repetitions.

When starting out with the inner biceps curl, it is important to use a weight that allows for proper form to be maintained throughout the exercise. Use an adequate amount of weight so that three sets of five to ten reps each can be performed. As strength and comfort with the exercise increase, the weight can be gradually increased to continue challenging the muscles. 

Benefits of the Inner Biceps Curl

One of the primary advantages of the inner biceps curl is that it more effectively targets the short head of the biceps than the traditional biceps curl. The exercise is performed with the shoulders externally rotated, which increases the activation of the short head. This can be especially beneficial for individuals who want to specifically target and strengthen the short head.

The inner biceps curl can also help to improve muscle imbalances. Many people tend to have stronger biceps on the outside of their upper arms due to the way that traditional biceps curls are typically performed. By incorporating inner biceps curls into a workout routine, it is possible to balance out the development of the biceps muscles and achieve a more symmetrical appearance.

Incorporating the inner biceps curl into a workout routine can be as simple as adding a few sets of the exercise to an existing arm day routine. It can also be included as part of a full-body strength training workout by pairing it with exercises for other muscle groups. 

Common Mistakes to Avoid

When doing inner biceps curls, instead of focusing on how much weight you can lift, prioritize getting the form right. Choose the appropriate amount of weight that can be raised in a fluid motion and lower the dumbbells in a slow and controlled manner to maximize muscle and strength gains.

The elbows should stay in a position that is relatively close to the side of the body, and the only part of the arm that should move is the forearm. The elbow position must be maintained throughout the range of motion. Always maintain a tall, upright spine and avoid swaying the body during the motion.

No Money Curls

The “No Money Curl” is a variation of the inner biceps curls invented by Jeff Cavaliere MSPT, CSCS, and became popular on his program in 2011. This variation looks similar to the inner biceps curl; however, they differ a bit in execution. 

While the inner biceps curl has the shoulders externally rotated all throughout the motion, the no money curl dynamically rotates the shoulders externally along with the movement of the weight to the top. It also requires forearm supination along with the motion.

Stand with the feet hip-width apart while holding a dumbbell in each hand using a neutral grip. Slide the hands onto one end of the dumbbells’ handles so that the thumbs and index fingers are touching the plates. This is done to provide more torque for the resistance when doing supination during the lift. Do not externally rotate the shoulders in this starting position.

While keeping the upper arm close to the sides of the body, lift the weight to the sides of the shoulder while slowly supinating to the top of the movement. The dumbbells should be going to the sides of the shoulders. Next, slowly return to the starting position while rotating the forearm back to the neutral position.

Final Thoughts

It is important to note that while the inner biceps curl can be a useful exercise for strengthening the biceps and improving functional fitness, it is not a standalone solution for achieving well-defined arms.

A well-rounded fitness routine that includes a variety of exercises for the upper body, as well as the rest of the body, is likely to be most effective for achieving overall fitness and wellness goals. In addition, proper form is essential when performing the inner biceps curl or any other exercise in order to avoid injury and maximize the benefits of the exercise.

In conclusion, the inner biceps curl is a valuable exercise for strengthening the biceps and improving functional fitness. It can be incorporated into a well-rounded fitness routine to help improve arm strength and definition, as well as contribute to overall physical health and wellness. By using proper form, the inner biceps curl can be safely and effectively performed to achieve fitness goals.

References

1. Jarrett CD, Weir DM, Stuffmann ES, Jain S, Miller MC, Schmidt CC. Anatomic and biomechanical analysis of the short and long head components of the distal biceps tendon. J Shoulder Elbow Surg. 2012;21(7):942-948. doi:10.1016/j.jse.2011.04.030

Debbie (Deb) started powerlifting and Olympic lifting in High School as part of her track team's programming; She continues to train in order to remain athletic. Inspire US allows Deb to share information related to training, lifting, biomechanics, and more.
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