The PowerBlock shoulder press performed seated strengthens the anterior shoulders and triceps. This strength training exercise also works the upper chest, serratus anterior and the trapezius muscles. Your lower back should be pressed against the bench, however your upper back can remain off the bench in order to allow the scapula to move. You may also perform the dumbbell shoulder press without back support to activate the core muscles.
Took a scientist to figure this one out.
MrRimrepair 8 months ago