Every guy wants to be biggest, strongest dude in the gym. Developing your shoulders will not only make you look like a badass, but it’s an easy way to pack on weight and increase your overall upper body strength.
There are several muscles that attach to and originate from the shoulder, but for the purposes of this article, we’ll be focusing on the the two biggest superficial muscles of the shoulder - the deltoids and the trapezii. The trapezius muscle serves to laterally rotate, elevate, and retract the scapula, while the deltoids abduct, flex, extend, and medially and laterally rotate the humerus.
Andrew Sacks Sports Performance 