There are a couple of different ways to work shoulder pressing into your workout. You can be seated or stand, and if you take machines out of the picture, you have a choice of using dumbbells or a barbell. A study published in the Journal of Strength and Conditioning Research shows the one rep max (1RM) and muscle activation tradeoffs involved in various combinations.
Testing 15 subjects working with 80% of their respective 1RM, scientists determined that anterior deltoid muscle activation was 15% lower when standing and 11% lower when seated using a barbell compared to dumbbells. On the other hand, biceps activation was 33% greater when seated using a barbell instead of dumbells. Triceps activation also favored the barbell, with a 39% increase in muscle activation while standing. 1RM was 7% lower when standing and 10% lower when seated if you went with dumbbells over a barbell.
True Strength Moment: Obviously, there’s good and not so great aspects to each shoulder press variation. If you work both the seated and standing options, switching between barbells and dumbbells, you’ll make the most of what each combination has to offer. For best results, stick with one option for a couple of weeks before trying another.