Shoulder joint muscles and movements

The shoulder joint is a ball and socket joint that allows for a great range of motion. In this post, we will explain how the shoulder joint muscles and movements are targeted through specific exercises. The bones in the shoulder are the scapula (shoulder blade), clavicle (collarbone) and humerus (upper arm bone).

These shoulder bones are connected by ligaments and tend to be quite strong. However, the shoulder is prone to injury as it is used in many different movements. This blog post will discuss the main muscles, bones, and actions of the shoulder and exercises to target these muscles. We will also look at stretches that improve the shoulder joint’s flexibility and range of motion.

Shoulder bones

The bones in the shoulder are the scapula, clavicle and humerus. The shoulder blade (scapula) provides a surface for muscles to attach to, whereas the collarbone (clavicle) is connected at both ends of the shoulder joint. The upper arm bone (humerus), which ties in the middle of the shoulder joint, allows for a wide range of motion.

Shoulder Joint muscles and movements

Muscles

The main shoulder muscles are the deltoid, trapezius and rotator cuff muscles. The deltoid muscle is responsible for abduction (lifting away from the body), extension (straightening out) and medial rotation (rotating towards the body) of the arm.

The trapezius muscle is responsible for horizontal abduction (lifting out to the side) and extension of the arm. The rotator cuff muscles are a group of four small muscles that stabilise and rotate the shoulder joint.

The shoulder muscles include the trapezius, rhomboids and deltoids. The trapezius is a large muscle that covers most of the back and neck. There are three parts to this muscle; upper traps, mid traps and lower traps which all work together in movements such as shrugging your shoulders or pulling something down.

The rhomboids are a pair of muscles that lie underneath the trapezius muscle. They attach to the shoulder blade and help retract it (pulling it towards the spine). The deltoids are the large, round muscles that make up the majority of the shoulder.

There are three parts to these muscles; anterior (front), medial (side) and posterior (back). The anterior deltoid is responsible for flexing the arm at the shoulder, while the medial and posterior deltoids are responsible for abduction (lifting away from the body) and adduction (bringing towards the body), respectively.

Movements

The shoulder allows for several different types of movement, including flexion, extension, abduction, adduction, internal and external rotation.

Flexion is the movement when you lift your arms in front of you, whereas extension occurs when you lower your arm down to the side of your body.

Abduction refers to lifting out to the side (e.g., lifting away from the midline), and adduction describes bringing towards or across the midline (e.g., bringing back towards the body). Internal rotation and external rotation refer to turning the shoulder inwards and outwards.

Ligaments connect the bones in the shoulder joint. There are two primary ligaments in the shoulder; the superior glenohumeral ligament and the inferior glenohumeral ligament. These ligaments attach the humerus to the scapula and keep the joint stable.

Shoulder Range of motion

The range of motion in the shoulder makes it one of the most mobile joints in the body. It is able to flex, abduct, adduct, rotate internally and externally, as well as several movements that combine these motions (e.g. lateral flexion). Because of this, many exercises can target the muscles in the shoulder joint.

Some examples of these include front raises, side raises and rear delt flyes for targeting different parts of the deltoid muscle; bent over rows for targeting the upper traps and rhomboids, the biceps; and shoulder press for targeting the anterior, medial and posterior deltoids.

It is essential to do stretches that target these muscles to improve flexibility and range of motion in the shoulder joint for instance.

Shoulder stretch (sleeper stretch)

How to:

  • lie on your side with your head resting on your arm.
  • Bend your top knee and place the bottom ankle on top of it. Gently pull the top shoulder towards the floor, feeling a stretch in the front of that shoulder.
  • Hold for 20-30 seconds and repeat on the other side.

Another great stretch for improving flexibility and range of motion is the

Shoulder overhead reach

How to:

  • Stand with your feet hip-width apart and raise your arms straight up towards the sky, palms facing each other.
  • Reach as high as you can, feeling a stretch in your shoulders.
  • Hold for 20-30 seconds and repeat.

Mens Shoulder muscles and movements shown by flexing muscles

Top 10 Shoulder exercises

The Below exercises will require a few simple pieces of equipment – I suggest starting with Bodyweight exercises and building to lightweights e.g Cans of soup or  bottles of water, Leading you to Kettlebells, Dumbbells and building to heaver sets using Barbells

#1 – Seated shoulder press

Target muscles: anterior, medial and posterior deltoids (Back).

How to:

  • Sit upright on a bench with your feet shoulder-width apart.
  • Hold the dumbbells at shoulder height with palms facing forwards and elbows pointing outwards.
  • Press the weights up until your arms are fully extended above you, then lower them back down
  • Repeat

#2 – Standing lateral raise

Target muscles: lateral deltoid.

How to:

  • Stand with your feet hip-width apart and hold a weight in each hand with your palms facing your thighs.
  • Keep your elbows slightly bent and raise your arms out to the sides until they are parallel to the floor.
  • Pause, then slowly lower them back down.

#3 – Front raise

Target muscles: anterior deltoid.

How to:

  • Stand with your feet hip-width apart and hold a weight in each hand with palms facing your thighs.
  • Keeping your elbows slightly bent, raise the weights out in front of you until they are parallel to the floor.
  • Pause, then slowly lower them back down.

#4 -Rear delt flyes

Target muscles: rear deltoid (back).

How to:

  • Sit down on a bench with your feet flat on the ground and shoulder-width apart.
  • Hold a weight in each hand with your palms facing each other and let them hang at arm’s length by your sides, bending your elbows slightly.
  • Keeping your back pressed firmly against the bench, lift your arms out to the sides until they are parallel to the floor.
  • Pause, then slowly lower them back down.

#5 – Bent over row

Target muscles: upper trapezius, posterior deltoid and rhomboids.

How to:

  • Stand with your feet hip-width apart and hold a weight in each hand.
  • Bend forward until your torso is at 45 degrees to the floor, then lift the weights towards your chest while keeping them close to your body.
  • Pause, then slowly lower them back down.

#6 – Shoulder shrugs

Target muscles: upper trapezius.

How to:

  • Stand with your feet hip-width apart and hold a weight in each hand with palms facing your sides.
  • Lift the weights towards your ears, then slowly lower them back down.
  • Keep your elbows slightly bent throughout the movement, and don’t rotate your shoulders as you lift.

#7 – Upright rows

Target muscles: anterior deltoid and upper trapezius.

How to:

  • Stand with your feet hip-width apart and hold a weight in each hand, with palms facing your thighs.
  • Lift the weights towards your chest, keeping them close to your body and leading with your elbows.
  • Pause when they are parallel to your chest, then slowly lower them back down.

Note: don’t jerk the weights up or use too much momentum.

#8 – Lateral raises

Target muscles: lateral deltoid.

How to:

  • Stand with your feet hip-width apart and hold a weight in each hand with palms facing your thighs.
  • Lift the weights out to the sides until they parallel the floor.
  • Pause, then slowly lower them back down.

Note: use slow and controlled movements.

#9 – Arnold presses

Target muscles: anterior and medial deltoids, upper trapezius.

How to:

  • Sit on a bench with your back straight, feet flat on the floor and shoulders width apart.
  • Hold the dumbbells at shoulder height in front of you with palms facing away from you.
  • Press until your arms are fully extended above you, then lower them back down to the starting position.
  • Keep your elbows slightly bent throughout the entire movement.

Note: Try not to rock or swing your body as you lift the weights.

for more Intensity, try doing these with one weight in each hand.

#10 – Reverse flyes

Target muscles: posterior deltoid.

How to:

  • Sit on a bench with your back straight, feet flat on the floor and shoulder-width apart.
  • Hold a weight in each hand with your palms facing each other and let them hang at arm’s length by your sides, bending your elbows slightly.
  • Keeping your back pressed firmly against the bench, lift your arms out to the sides until they are parallel to the floor.
  • Pause, then slowly lower them back down.

Note: Keep your torso still throughout the movement, and don’t arch or round your back as you lift.

Try not to strain or pull on your neck muscles as you lift.

Top 5 Causes of shoulder injuries

A woman showing signed of injuries to the shoulder muscles

Due to the complexity of the shoulder, joint injuries can occur pretty quickly, even from simple everyday activities such as lifting and reaching.

The shoulder is also prone to injury as it is used in many different movements. The most common injuries are rotator cuff tears and impingement syndromes. These injuries are caused by overuse or trauma to the shoulder.

A shoulder injury can be any damage to the joints, muscles, tendons or ligaments in your shoulder that may affect your ability to move it.

Here are five of the most common causes of shoulder injuries:

#1 – Overuse

Overuse of the muscles and tendons can lead to inflammation and tears.- This is usually a result of repetitive activities such as sports or work tasks that involve the shoulder. The constant use of the shoulder muscle can build load quickly and its link to the other main areas of the upper body can cause this to happen without forward planning.

#2 – Trauma

A direct blow to the shoulder, such as from a fall or accident, can cause damage to the joints, ligaments, muscles or tendons.

#3 – Poor posture

If you have poor posture or do not use correct lifting and carrying techniques, you increase the risk of a shoulder injury.

#4 – Age

Shoulder problems are more common in people over 40 years old as they lose flexibility and muscle strength with age.

#5 – Arthritis

This is inflammation caused by wear-and-tear that occurs over time. It can lead to joint pain, stiffness and swelling.

Conclusion

The shoulder is a complex joint that is responsible for many different movements. It is essential to understand the muscles and bones that make up this joint and the exercises and stretches that can target these muscles. Doing so will help to keep the shoulder healthy and flexible. Thanks for reading!

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