Most women work their shoulders by doing a pressing movement or a side raise and neglect the posterior portion, which is very important when it comes to posture, say John Dull and Michelle Collier, both certified personal trainers and co-creators of the Supreme 90-Day System. Strengthening your rear deltoid muscles helps to pull your shoulders back. Most exercises that we do cause us to protract our shoulders and collapse our posture forward, accompanied by a forward head tilt and a weak core.
Best Exercise: Bent Over Raise
Holding dumbbells in each hand, bend forward at the hips, keeping your back flat and knees slightly bent. Let your arms hang straight down in front of you, slightly bent, and raise the dumbbells away from your body until they are parallel with your back. Pause for a second and then lower them back down with control, being careful not to swing your arms. Do 3 sets of 15 reps each. (Be sure to choose a weight that will fatigue your muscles by the last rep in each set, but not be too heavy that you can't finish each rep with proper form).