Which Muscles Does the One-Arm Dumbbell Press Work?

Seated or standing, the overhead press is a great exercise.
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The one-arm dumbell press involves pressing a single weight above your head from shoulder level. Pressing a weight above your head is a traditional feat of strength and is also part of the sport of Olympic lifting. The overhead press was once a stand-alone Olympic event but problems with judging and safety resulted in its stand-alone demise in 1972. Today, the overhead press is part of the Olympic "clean and jerk" event.

The Overhead Press

The overhead press, often simply called "the press," can be performed seated or standing using a pair of dumbbells or a single dumbbell. It can also be done using a barbell or kettlebell. Using a single weight increases the number of muscles affected by this exercise because you have to resist the temptation to lean over to the side and must work extra hard to keep your spine and shoulder stabilized. Perform this exercise in the standing position and even more muscles are involved in keeping your form and balance.


The muscles doing the majority of the work in an exercise are commonly called the agonists. In the one-arm press, the agonists are the deltoids, or shoulder muscles. There are three deltoids: anterior, medial and posterior. The anterior deltoid, located at the front of your shoulder, is the most active in the one-arm press. The other shoulder muscles act as helpers rather than prime movers.


Muscles that help the agonists are called synergists and can be thought of as secondary or helper muscles. The main synergists in the one-arm press are the medial and posterior deltoids; the triceps, located on the back of the upper arm; the trapezius of the shoulder girdle; and the supraspinatus of the rotator cuff. These secondary, smaller muscles are often the ones that fatigue first when performing one-arm presses. You will know you are reaching fatigue when you can no longer fully extend your arm overhead.


Fixators ensure your joints remain aligned properly so you can safely perform an exercise or movement. If the press is performed in the standing position, all of your leg muscles can be included in this category as they must remain contracted to keep you upright. If you are performing the press sitting on an exercise bench, the bench will provide some support and fewer muscles will be called upon.

Seated or standing, the one-armed, and therefore one-sided nature of this exercise, means that you will need to use your obliques in your waist, your spinal erectors and your rectus abdominus to keep your spine vertical and prevent any side-to-side movement as you press the weight up and overhead. If you actively try and lean into each lift in an attempt to generate more force, these muscles become synergists rather than fixators.


Antagonists are the muscles that oppose the agonists and are usually located on the opposite side of the same joint. For the overhead dumbbell press, in order to press your arm up and overhead with your shoulder muscles, the muscles below your shoulder, namely your latissimus dorsi, or lats for short, must relax to allow movement to occur. This is called reciprocal inhibition and is an important aspect of virtually all human movement.

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