An effective approach must include both stretching the muscles that commonly become tight as well as strengthening those that are often weak. Now, the majority of desk workers end up slouching forward when tired. This slouching forward posture tightens the muscles around the front of the shoulders, arms, chest and neck, while over-stretching and weakening the muscles around the upper back.
So, to follow this simple idea, the muscles in the front of the body therefore need to be lengthened back to their optimal, resting length, while the muscles at the back need to be shortened and strengthened. It can, of course, be more complicate than this, but let’s stay with this simple, common approach.