The shoulder is made up of three deltoids – the anterior (front), lateral (middle/side), and posterior (rear) head.
Many people under work the lateral deltoids by expecting side raises to train them.
However side raises need a slight tweak to suitably train the lateral deltoids.
With side raises, other muscles (anterior deltoid and supraspinatus) are used as much as the lateral deltoids, which are supposed to be the main muscle worked.
So how do you train the middle shoulder without involving the front?
Changing to an incline bench side raise (face to the bench) helps isolate the lateral deltoids. The first 30° of motion works the supraspinatus, but after that the lateral deltoids are isolated.
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Therefore it is best to control the motion at the top.
What’s more, internal rotation of the shoulders will further involve the lateral deltoids.
As for the posterior delts, you can train them with any type of pulling motion, such as face-pulls (that brings the elbow behind the body).
For front delts, overhead presses generally provide enough of a workout, however the front raise in the scapular plane with the shoulder externally rotated can also be added.
To train the external rotators, face-pulls or side-lying external rotations are recommended.
The side-lying external rotations allow for full range of motion.
Shoulders are 60% slow-twitch dominant, with the exception of the infraspinatus (part of the rotator cuff) which is marginally fast twitch dominant.
The muscles are actively involved in maintaining posture and stabilizing the shoulder during most upper body movement.
Therefore use relatively high to medium reps.
Take home messages
• Traditional shoulder programs emphasize the anterior deltoid at the expense of the rest of the scapula-humeral muscles.
• Overhead presses are generally plenty of work for your anterior deltoids.
• Add incline side raises and reverse flys with your shoulders internally rotated to balance the program and round out your delts.
