New exercises are always being developed, and it is easy to forget that some of the traditional ones actually do a better, more rounded job to improve your fitness. The shoulder press can be completed using a fixed resistance machine or by using free weights to stimulate your core muscles while exercising. This exercise is suitable for all abilities and ages and can be used to develop muscular strength or endurance.
Completing a Shoulder Press
If you are using a fixed-resistance machine, it is very simple to follow the instructions for that device. If you are using free weights, do so with an upright back support. Sit with your feet flat on the floor and hold the barbell or dumbbells level with your shoulders; when you're ready, fully extend your arms above your head but do not lock your elbows. Hold for a moment and then lower and repeat. Have someone spot you from behind in case the weight is too heavy.
Anatomy of the Shoulder
Your shoulder is made up of three bones: the clavicle, scapula and humerus. They all meet to form the shoulder joint and are connected by ligaments. The muscles that control the shoulder are the deltoids -- front, middle and back -- which are the large, rounded muscles that cover your shoulder. The triceps are also used heavily in a shoulder press along with the pectorals, which support the movement, while the core muscles engage to stabilize you as you lift the weight.
Understanding the Deltoids
When performing the shoulder press, the deltoids are the prime movers. Three individual muscles make up the deltoids divided by location: anterior -- or front; middle; and lateral -- or back. When you fully extend your arms, you mainly activate your anterior deltoid but still use the whole muscle. Changing the width of your grip will alter how much of the deltoid you are activating, so vary the width in training.
The Role of the Triceps
The triceps muscle is found on the rear of your upper arm; its main function is to straighten your arm. Your triceps are secondary muscles, which cause your arm to extend during the shoulder press. You use them more heavily in the downward phase to help you slowly lower the weight safely rather than dropping it. This causes more stress to the muscle than the lift phase and is known as working the muscle eccentrically.
Core Muscles Involvement
When you perform a shoulder press, all of your core is active to stabilize your body so that you can lift the bar above your head. Your core muscles consist of your abdominals, obliques -- the outer edge of the stomach -- and the lower-back muscle called the latissimus dorsi. This is a great exercise to use to improve whole-body strength. You can increase the difficulty by standing up, which forces your core muscles to work harder.