The shoulder muscles (deltoideus muscles, deltoids, or delts) get their name from their delta (triangular) shape and are located on top of the shoulder joint. Their primary function is to elevate the arm. The side head performs most of the work until the arm reaches about 60 degrees; beyond that point, the front and rear heads become more involved. The deltoid muscle forms the rounded contour of the human shoulder.
Find exercises and more information about other muscles at Weight Training Main.
Description
The shoulder muscles consist of three deltoid heads:
- Pars Clavicularis – Front Head – Front Deltoids
Activated when lifting something in front of you (with your thumbs pointing upward).
Typical Exercise: Front Dumbbell Raise - Pars Acromialis – Side Head – Middle Deltoids
Activated when lifting something to the side.
Typical Exercise: Side Lateral Raise with Dumbbells - Pars Spinalis – Rear Head – Rear Deltoids
Typical Exercise: Reverse Fly
Overview
A typical shoulder exercise that is excellent for building overall strength and mass is the barbell military press. When performed sitting upright, it engages the entire shoulder. If you lean the backrest slightly, the front deltoid head becomes more active. However, if you lean back too far, the movement turns into an incline bench press, targeting the chest instead of the shoulders.
Advice
- When performing front or side dumbbell raises, do not lift the weights above shoulder level. The deltoid’s role is to lift the arm and stabilize the upper arm bone within the shoulder joint. Raising the arm too high changes the angle of force and can stress the joint unnecessarily.
- During the military press, other muscles (like the triceps) assist and help stabilize the shoulder joint.
- One of the best exercises to train the rear delts is the reverse fly.
- To avoid shoulder imbalances or injury, train all three deltoid heads.
- The only shoulder exercise suitable for heavy weights is the military press.
- You can also build shoulder strength with handstand push-ups.
Exercises
- Standing Barbell Military Press
- Side Lateral Dumbbell Raise
- Front Dumbbell Raise
- Plate Front Raise
- Reverse Dumbbell Fly
- Cable Internal Rotation
- Arm Circles
Suggestions
- Skeletal Muscle System
- Chest Muscles
- Back Muscles
- Biceps
- Triceps
- Forearm Muscles
- Leg Muscles
- Abdominal Muscles
