Personal Trainer Michael Behnken, MS, NASM-CPT-PES, CSCS
Dumbbell shoulder press is an effective shoulder exercise for building strength as well as muscle definition.
To perform this exercise properly make sure you do not arch your back.
Arching your back not only puts your back in danger, but also cheats your medial deltoids out of work as your clavicular pecs and anterior deltoids get recruited.
You can perform seated with back support, on a stability ball, or standing.
If you perform standing, the same rules apply. Contract your glutes and keep your core tight during the duration of the movement so your lower back does not arch.