When you are performing the shoulder press, you are using far more than three muscles to execute the lift. The arm muscles are the prime movers in the shoulder press, but the muscles of your trunk and core contract to stabilize you when you are lifting.
Although your body uses more than three muscles during the shoulder press, the prime movers are the deltoid, trapezius and triceps.
Shoulder Press: Muscles Used
The shoulder press is primarily performed by muscles in your shoulder, with help from your chest and arm muscles.
1. Anterior Deltoid and Shoulder Presses
The deltoid muscles at the top of your shoulders are one of the prime movers in the shoulder press. The deltoid has three parts — anterior deltoid at the front, lateral deltoid along the outside of your shoulder, and the posterior deltoid on the back of your shoulder. The function of the deltoid as a whole is to raise the arm overhead.
During the shoulder press, the anterior deltoid is the most active part of this muscle group.
2. Triceps and Shoulder Presses
The triceps are the large muscles on the back of your upper arm. Although the triceps cross both the shoulder and elbow joints, these strong muscles straighten your elbow joint during the shoulder press. To target the triceps even more, perform a close-grip barbell shoulder press. The closer your hands are on the bar, the greater the activation of the triceps.
3. Trapezius and Shoulder Presse
Your upper back helps stabilize your shoulders during the shoulder press. The trapezius is a large muscle that spans from the base of your skull to the middle of your back, and across the top of your shoulders. It has three parts — the upper, middle and lower traps.
During the shoulder press, the middle and lower trapezius muscles assist with rotation of your shoulder blades as your arms reach overhead.
Read more: Muscle Usage in an Overhead Press
Muscles that Stabilize
Many muscles do little more than maintain proper positioning during the shoulder press, but are critical. The internal and external shoulder rotators are both working to keep your shoulder joint stable. Your abdominals and lower back contract to maintain your torso in an erect position, and the finger flexors in your forearms contract to allow you to hang on to dumbbells, a barbell or handles on a lever shoulder press machine.
Read more: Incline Bench vs. Military Press
Use Proper Form
To effectively target the muscles used in the shoulder press, be sure to use proper form. If you are new to this exercise start with the shoulder press machine.
- Adjust the seat height so that the handles are approximately shoulder-height.
- Sit on the seat and hold the handles using an overhand grip.
- Tighten your core muscles and press the handles straight overhead.
- Hold for one to two seconds, then lower back down.
- Perform 10 repetitions, working up to three sets in a row.
When performing free weight shoulder press, use light dumbbells until you've mastered the technique.
- Straddle a weight bench or sit on a firm surface with your feet flat on the ground.
- Holding one dumbbell in each hand, bend your elbows and raise your hands to shoulder-height.
- Rotate your forearms until your palms face forward.
- Press the dumbbells up overhead until your elbows are straight, then slowly lower back down.