Barbell or dumbbells
Pressing overhead uses the front and side deltoids, while the upper and lower traps and serratus anterior rotate the shoulder blades upward so the arm can reach full height.
| Muscle | Role | Action |
|---|---|---|
| Anterior deltoid | Primary | Flexes and medially rotates the arm at the shoulder |
| Lateral deltoid | Primary | Abducts the arm (raises it out to the side) |
| Triceps brachii | Secondary | Extends the elbow; the long head also extends the arm |
| Upper trapezius | Secondary | Elevates and upwardly rotates the scapula |
| Lower trapezius | Secondary | Depresses and upwardly rotates the scapula |
| Serratus anterior | Secondary | Protracts the scapula and rotates it upward |
| Supraspinatus | Secondary | Assists the deltoid in abducting the arm and holds the humeral head in the socket |
| Pectoralis major | Secondary | Flexes, adducts and medially rotates the arm |
Primary muscles are the prime movers; secondary muscles assist or stabilise. The balance shifts with grip, stance, range of motion and technique.