How do I get wider shoulders?

Train the lateral (side) deltoid. It is the head that sits directly on the outside of the shoulder, so it is the one that adds visible width. Lateral raises, cable lateral raises and upright rows target it; pressing does not do much for it.

Why are my rear delts so weak?

Because most programmes press far more than they pull horizontally. The rear deltoid only works during shoulder extension and external rotation, which almost nothing in a press-heavy routine trains. Adding rear-delt flyes or face pulls two or three times a week closes the gap quickly.

Is the overhead press enough for shoulders?

No. It trains the anterior head heavily and the lateral head partly, but the posterior head barely at all. A complete shoulder needs a press, a lateral raise and a rear-delt movement.

Should I train shoulders on their own day?

You do not have to. The side and rear heads are small and recover quickly, so spreading them across two or three sessions per week tends to work better than a single dedicated shoulder day.

Upper body

Shoulders

Deltoideus

Also called: delts, deltoid muscle, shoulder muscles

The deltoid is a three-headed muscle capping the shoulder. The anterior head raises the arm forward, the lateral head raises it out to the side, and the posterior head pulls it backward. Each head needs a different movement, which is why pressing alone never builds complete shoulders.

front

back

The shoulders highlighted on the front and back of the body.

Shoulders anatomy

The deltoid wraps the shoulder joint from front to back, originating along the outer third of the collarbone, the acromion and the spine of the shoulder blade, and converging into a single tendon on the outside of the upper arm.

Because the three portions attach at different points, they pull the arm in different directions and are functionally almost separate muscles. Training one does very little for the others.

The rotator cuff — supraspinatus, infraspinatus, teres minor and subscapularis — sits underneath. It does not contribute much to shoulder size, but it keeps the humeral head centred in the socket, and neglecting it is a common thread in shoulder complaints.

Part	What it does
Anterior (front) deltoid	Shoulder flexion and internal rotation. Already heavily trained by every press — rarely needs isolation.
Lateral (side) deltoid	Shoulder abduction. This is the head that creates shoulder width. Trained by lateral raises and upright rows.
Posterior (rear) deltoid	Shoulder extension and external rotation. The most commonly undertrained head in the body.

Origin: The lateral third of the clavicle, the acromion, and the spine of the scapula.
Insertion: The deltoid tuberosity on the lateral surface of the humerus.

What the shoulders does

Shoulder abduction — raising the arm out to the side (lateral head, primarily between 15° and 90°).
Shoulder flexion — raising the arm forward (anterior head).
Shoulder extension — driving the arm backward (posterior head).
Internal rotation (anterior head) and external rotation (posterior head).
Stabilising the humeral head in the glenoid during any loaded arm movement.

Best shoulders exercises

Exercise	Equipment	Role	Level	Why
Overhead press	Barbell or dumbbells	primary	Intermediate	The heaviest shoulder movement. Trains the anterior head hard, with the lateral head assisting.
Dumbbell lateral raise	Dumbbells	primary	Beginner	The single best lateral-head exercise. Light weight and strict form beat heavy swinging every time.
Cable lateral raise	Cable machine	primary	Beginner	Keeps tension on the delt at the bottom of the range, where dumbbells provide almost none.
Reverse pec-deck flye	Machine	primary	Beginner	The most reliable rear-delt isolation — the machine path stops you turning it into a row.
Face pull	Cable machine + rope	primary	Beginner	Trains the rear delt and external rotators together. One of the few genuinely useful 'shoulder health' exercises.
Bent-over reverse flye	Dumbbells	primary	Beginner	Free-weight rear-delt work. Keep the torso still — momentum here defeats the whole point.
Arnold press	Dumbbells	secondary	Intermediate	Adds rotation through the press. More range of motion than a standard press, at the cost of load.

How to train the shoulders

Sets per week

Lateral head 10–20 sets; rear head 8–16; front head usually 0–6 direct

Rep range

6–10 for presses, 12–20 for raises and rear-delt work

Frequency

2–3 sessions per week for the side and rear heads

Count your pressing volume as front-delt volume. If you bench twice and overhead press once a week, the anterior deltoid is already well fed and rarely needs isolation.
The lateral and rear heads are small, recover fast and respond well to higher frequency — spreading raises across three sessions works better than one long shoulder day.
Rear-delt work is the highest-value thing most lifters are not doing. It balances out heavy pressing and is cheap in terms of fatigue.

Stretches and mobility

Cross-body shoulder stretch

Pull one arm across the chest with the opposite hand, keeping the shoulder down. 30 seconds each side.

Sleeper stretch

Lie on the target side, shoulder at 90°, gently rotate the forearm toward the floor. Go easy — this one is often overdone.

Common mistakes

Going too heavy on lateral raises

The lateral deltoid is a small muscle with a short lever. Once you start heaving the weight up with a hip drive, the traps take over. Half the weight and a controlled tempo trains it far better.

Ignoring the rear delt entirely

Most training programmes contain far more pressing than horizontal pulling, and the rear delt is the muscle that pays for it. Two sets of face pulls at the end of every upper-body session fixes most of it.

Adding front raises on top of heavy pressing

The anterior deltoid is worked by every bench press, incline press, dip and overhead press you do. Direct front raises are usually redundant volume that just adds fatigue.

Shoulders FAQ

How do I get wider shoulders?: Train the lateral (side) deltoid. It is the head that sits directly on the outside of the shoulder, so it is the one that adds visible width. Lateral raises, cable lateral raises and upright rows target it; pressing does not do much for it.
Why are my rear delts so weak?: Because most programmes press far more than they pull horizontally. The rear deltoid only works during shoulder extension and external rotation, which almost nothing in a press-heavy routine trains. Adding rear-delt flyes or face pulls two or three times a week closes the gap quickly.
Is the overhead press enough for shoulders?: No. It trains the anterior head heavily and the lateral head partly, but the posterior head barely at all. A complete shoulder needs a press, a lateral raise and a rear-delt movement.
Should I train shoulders on their own day?: You do not have to. The side and rear heads are small and recover quickly, so spreading them across two or three sessions per week tends to work better than a single dedicated shoulder day.

References

This page is general educational information about exercise and anatomy. It is not medical advice and not a substitute for assessment by a qualified clinician. If you have pain, an injury or a health condition, speak to a professional before changing how you train.