Excessive barbell pressing can deepen these symmetry issues and lead to drastic strength and size imbalances in the upper body. You could be simply applying more force on your right/left side for years and even contorting your body in favor of your stronger side and not notice it until the imbalance becomes painfully visible.
Here’s where dumbbells come to the rescue yet again. Dumbbell presses can ensure that both sides of your body receive equal amounts of work and spread the tension placed on the muscles more evenly. By having each side work independently to move the weight, you will prevent your dominant side from constantly helping out the weaker one and balance out any existing muscle imbalances in the long run.
#3. Mechanical Tension
When using a barbell, your hands naturally move outward as you press the weight. This outward push calls other supporting muscles into play, namely the triceps and shoulders, and accentuates their role in the lift. As you can imagine, the shift of tension decreases the stimulus for chest growth and we suppose you want the exact opposite of that.
To enable maximum tension on the targeted muscle, you need to make sure that your pecs are doing the majority of work during every single rep. Dumbbells have the ability to place slightly more tension on the chest muscles than a barbell and they also keep the muscles under tension for longer because of the greater range of motion, so consider incorporating dumbbell presses to your chest routine to reap this benefit and exhaust your pecs more thoroughly.
In addition, certain studies have also shown that compared to the standard barbell variant, dumbbell presses offer greater advantages in terms of muscle activation. One study from York University tested this claim with the help of electromyography and found that all three basic variants of dumbbell presses (flat, decline and incline) have the potential to activate more pectoral muscle fibers than their barbell counterparts.
Although a barbell allows you to lift heavier weights, this factor alone is not enough to ensure optimal muscle growth. With the use of dumbbells you can amplify the effectiveness of your lifts by increasing the volume and duration of the tension placed on the pecs. So if you want top results, make sure you get the best from both worlds by combining both exercises into your chest routine.