Arnold Press: Benefits, Muscles Worked, and More

The Arnold press is a classic upper body exercise with a rather unique muscular recruitment pattern, as it targets both push and pull muscles in a single fluid motion.

Those seeking a change in their training program or less time spent doing accessory movements will both benefit from including the Arnold press into their workout plan.

But before picking up a pair of dumbbells and twisting your arms upwards, it is important to fully understand what the Arnold press is in the first place. 

What is the Arnold Press?

In technical classification, the Arnold press is considered to be an open chain compound movement involving arm extension and large scale rotation of the shoulders and wrists.

While the Arnold press is most often compared to the dumbbell overhead press in terms of movement pattern and mechanics, the former exercise is made far more unique by featuring a twisting motion as the weight is pushed overhead.

The Arnold press is most often performed so as to target the entirety of the deltoids in a more comprehensive manner - or as a method of saving the lifter time by targeting muscles that are not otherwise worked with conventional shoulder press variations.

A Note On Shoulder Health and the Arnold Press

Because of the twisting movement performed during each repetition of the Arnold press, lifters susceptible to injuries of the rotator cuff or the shoulder joint itself may find the Arnold press particularly dangerous.

If you have a history of injuries to the shoulder structure, the Arnold press may not be the right exercise for you.

Likewise, performing the Arnold press with the arms parallel to the sides of the head will also increase the risk of the same injuries, regardless of your injury history.

Is the Arnold Press the Right Exercise for You?

The Arnold press is somewhat more complex and requires greater shoulder mobility than conventional dumbbell shoulder presses. As such, at least an intermediate level of training experience should be present.

The Arnold press is most beneficial to bodybuilders and other hypertrophy-focused weightlifters that wish to target many of the smaller muscle groups of their upper body in a comprehensive and efficient manner.

How to do an Arnold Press

To perform a repetition of the Arnold press, the lifter will first begin by holding a pair of dumbbells at shoulder-height, palms facing inwards. The head should be facing forwards, chest pushed out and the core braced. If performing the exercise in a standing position, squeeze the glutes for greater stability.

Now in the correct stance, the lifter will push through their palms and extends their arms upwards. As they do so, the wrists should twist outwards as the dumbbells pass the face, ending with the palms facing forwards as the arms lock out overhead.

With the arms now extended over their head, the lifter will slowly reverse the motion by bending at the elbows and rotating their wrists until their palms are facing inwards once more.

Once the dumbbells have returned to their original position around shoulder-height, the repetition is considered to be complete.

Remember to perform both the overhead extension and the wrist rotation movement in a simultaneous manner. In addition, the arms themselves should begin slightly ahead of the skull, rather than immediately to the sides. This will help reduce stress on the shoulder joints.

What Muscles are Worked by the Arnold Press?

The Arnold press is classified as a compound movement, meaning that more than a single muscle group is dynamically contracted throughout its movement pattern. 

However, apart from these muscles being contracted in a dynamic manner, there are several others utilized in an isometric capacity. These muscles are known as “stabilizers”, and support the mobilizer muscles during the Arnold press.

Primary and Secondary Mobilizer Muscles

The Arnold press primarily targets all three heads of the deltoids muscle group, but will also work the biceps brachii, triceps brachii and the serratus anterior to a lesser extent as well.

Each of these muscles plays a dynamic role during a certain portion of the exercise’s range of motion, allowing them to develop in terms of strength and mass.

Stabilizer Muscles

Apart from the mobilizer muscles, the trapezius, pectorals and the biceps (after twisting) are all contracted isometrically throughout the movement as well.

Unlike the mobilizer muscles, the stabilizer muscles are less likely to undergo intense hypertrophy or strength development - save for the biceps, which are contracted dynamically during the start and end of the repetition.

What are the Benefits of Doing the Arnold Press?

The Arnold press is most commonly performed so as to achieve one or all of the following benefits.

Excellent for Targeting All Three Heads of the Deltoids

The Arnold press is one of the most effective exercises for targeting the entirety of the deltoid muscle group in a single motion. 

This is quite uncommon among deltoid exercises - even with various shoulder press variations, as most will only target the anterior or medial heads.

The majority of bodybuilders will generally perform 2-3 exercises in order to truly create a comprehensive shoulder workout. This can be time consuming and still lead to muscular imbalances due to the nature of many pressing exercises.

Fortunately, the Arnold press does not suffer from the same disadvantages and will save the lifter both time and any risk of developing an unbalanced deltoid muscle group.

Comparatively Wider Range of Motion

Because the Arnold press begins in a supinated shoulder-height position, the entire movement is comparatively larger than what one would experience with regular shoulder presses.

With a larger range of motion, a greater time under tension is achieved - as well as greater contraction of the mobilizer muscles as they are stretched to a greater length.

Generally, when training for hypertrophy or similar goals, a larger range of motion is always preferable. The Arnold press excels in this category as a shoulder exercise.

Reinforces Rotation of Wrists and Proper Shoulder Positioning

When performed carefully and with a slow tempo, the Arnold press is excellent for reinforcing proper rotation of the wrists and conscious positioning of the shoulders.

Ensure that proper form is followed and that the head, neck and upper back remain vertically aligned if performing the Arnold press for this purpose - or any other purpose, for the matter.

Perfect for Full Body Workout Programs

Because the Arnold press targets the biceps and serratus alongside the deltoids, it can be difficult programming it into a strictly push or pull day workout session. However, with this difficulty also comes the unique opportunity for inclusion into a full body training plan.

Whether after the bench press or a few sets of rows, the Arnold press nonetheless meshes quite well into such training sessions. It can even be used as the primary compound movement in a more shoulder-focused upper body workout plan.

Common Arnold Press Mistakes

In order to get the most out of the Arnold press and prevent any injuries, avoid the following common mistakes.

Incorrect Starting Position

One of the most important aspects of performing an Arnold press is beginning in the correct position. 

Beginning the exercise with the hands too high can reduce its effectiveness by shortening the range of motion. Likewise, beginning with the arms too wide apart or parallel to the sides of the torso can strain the rotator cuff.

Some advise performing the first half of a bicep curl with the dumbbells prior to starting the set, which should place the dumbbells at the correct height and position the forearms in the correct orientation.

Curving the Upper Back

Like in many other exercises, rounding the upper back during a set of Arnold presses can strain the cervical spine and affect the entire body’s stance itself. 

Poor upper back curvature could be a sign that the head and neck are incorrectly positioned, that too much weight is being lifted or that the lifter is failing to properly set their shoulder blades in a neutral position.

In order to prevent injuries related to this particular mistake, it is important to keep the chest pushed out and upright - as well as to ensure that the scapula is set in a manner that supports proper upper back curvature.

Jutting the Neck Forwards

In a similar case to improper upper back curvature, jutting the neck forwards or tucking the chin excessively can both compromise the integrity of the lifter’s stance. 

Common signs that this mistake is being made are a sensation of tightness in the trapezius, the shoulders rotating inwards or poor upper back curvature as well.

Furthermore, pushing the head forwards at the apex of the repetition will place undue strain on the elbows and shoulders - as well as potentially lead to impingements or even a loss of control over the dumbbells.

To avoid unconsciously making this mistake, the lifter should fix their eyes on a spot several feet away at head-height. The neck should be aligned over the shoulders in a relaxed manner. 

Asynchronous Rotation of the Wrists

During a repetition of the Arnold press, the motion of both extending the arms upwards and twisting the wrists should be performed simultaneously. Avoid extending the arms and then twisting the wrists in a non-simultaneous manner, as this can strain the wrists and forearms if done while in a fully extended position.

Locking Out the Elbows

Although the arms are indeed meant to extend upwards during the apex of the movement, it is good practice to avoid completely locking out the elbows as this can lead to several issues. 

Most important of these issues is excessive strain on the elbow joint, which is primarily a result of vertical pressure while in a completely extended state. 

However, asides from this, fully extending the elbows overhead will require the shoulders to rotate externally to a greater extent, creating greater difficulty maintaining proper form and potentially causing strain to the joint itself.

Aim to extend the arms just shy of fully extended over the body. Not only will this keep the upper body safe, but it will also help maintain tension throughout the deltoids as well.

Alternatives to the Arnold Press

If the Arnold press isn’t as efficient or isolated as you would like, try the following alternative exercises out.

Conventional Dumbbell Shoulder Presses

If the Arnold press is creating symptoms of pain and soreness in your joints, it may be time to try an alternative with less rotation. One of the closest of these is simply the regular dumbbell shoulder press - of which requires no twisting and is strictly a vertical pushing movement.

Even if the Arnold press is agreeable with your own physiology however, several training goals may require the more targeted and focused training stimulus of the strict shoulder press.

If you wish to create a greater focus on the anterior deltoids, lift more weight for the purposes of strength training, or wish to avoid targeting the biceps; then the conventional dumbbell shoulder press is best.

Incline Supinated Dumbbell Chest Press

For even greater time under tension on the biceps and upper body, performing an incline chest press with an underhand grip is one unconventional strategy to take. 

Although recruitment of the posterior deltoids in this alternative is minimal, it makes up for it by working the pectorals, triceps and anterior deltoids to a far more intense degree than the Arnold press.

The incline supinated chest press is a suitable alternative if you are performing the Arnold press for reasons other than comprehensive deltoid muscle group recruitment, such as for carryover to chin-ups or incorporating into a full body workout session.

Kettlebell Halos

If performing the Arnold press to target all three heads of the deltoids, few exercises are as effective a substitute as the kettlebell halo.

Kettlebell halos involve the lifter rotating a halo around their head and shoulders in a circular motion, both hands gripping the handle with one arm set behind or above the head.

Although kettlebell halos have received a similar level of controversy to the Arnold press (for the same reasons) - they allow for a more neutral shoulder position to be adopted, and are considerably less taxing on the biceps and triceps brachii.

Frequently Asked Questions (FAQ)

What does an Arnold Press Work?

The Arnold press targets all three heads of the deltoid muscles alongside the biceps brachii, triceps brachii and serratus anterior muscles. 

Is the Arnold Press Actually Better?

In certain aspects, the Arnold press is superior to other shoulder press variations. The most important of these advantages is its capacity to target all three heads of the deltoids alongside the biceps - something most shoulder presses cannot do effectively.

Why is it Called the Arnold Press?

The Arnold press is referred to as such because of Arnold Schwarznegger, a renowned bodybuilder, actor and politician who was crowned Mr. Olympia 7 times.

Closing Ideas

The Arnold press is only as effective as your mobility and technique allow it to be. Ensure that you have no issues with your rotator cuff, wrists or shoulders prior to performing it.

Because the Arnold press is so comprehensive in terms of targeting the smaller muscles of the upper body, those strapped for time can easily substitute several isolation exercises for the Arnold press alone. Just remember to compensate with volume and intensity.

References

1. Raizada, Shiny & Bagchi, Amritashish. (2017). Comparison among the EMG Activity of the Anterior Deltoid and Medial Deltoid During Two Variations of Dumbbell Shoulder Press Exercise. Indian Journal of Public Health Research & Development. 8. 653. 10.5958/0976-5506.2017.00411.9.

2. Hansen, John. Natural Bodybuilding. United States: Human Kinetics, 2005. ISBN: 9780736053464, 0736053468