shoulder impingement – the cause of most shoulder pain – explained!

Do you have shoulder pain? 

At Quay Health we are fortunate to have a fantastic personal training and group fitness studio on the ground floor of our building called Actual Fitness. As a PT studio, pushing people towards their physical and mental limits is all in a days work, however a recurring frustration for many of the clients and PT’s that stops them from achieving this is pre-existing shoulder pain that limits what the client can and can’t do.

Having shoulder pain while exercising can be frustrating, and can often lead to someone thinking  ‘maybe exercise is not for me’. Now, while taking time off from exercise to rest or recover from an injury is sometimes necessary, taking time off ‘forever’ and giving up on your health and fitness goals for good is not a great long term plan! Luckily, the PT’s know that the best long term outcomes come from their clients having their shoulder looked at, the cause of their pain identified, and a lasting solution put in place- and that’s when I get the call!

What causes shoulder pain?

If I were to list off every possible cause of shoulder pain, I could fill a text book. Luckily however, in the context of ‘office-workers who work out’, most shoulder pain can be labeled ‘shoulder impingement’ or ‘sub-acromial impingement’, so if this is you (office worker with shoulder pain), read on and I’ll explain a little about what is happening in your shoulder.

Anatomy of sub-acromial impingement

Anatomy of the shoulder The bone on the tip of your shoulder is called the Acromion. Between the Acromion and the humerus (your upper arm bone) is known as the ‘sub-acromial space’ (sub= ‘under’. As in ‘submarine).

The acromion therefore is the bony structure that forms the roof of this space and the humerus forms the floor. Diagram 1 explains this well.

In this space there are three main structures: 1) the Supraspinatus tendon (part of the rotator cuff), 2) the long head of the biceps tendon (not the short head) and 3) the subacromial bursa.

‘Sub-acromial impingement’ occurs when  one of these three structures is pinched.

Causes of sub-acromial impingement 

The sub-acromial space is usually about a ‘pinky width’ in space. If the space is adequate, most people won’t get pain. If the space is narrowed however, one or all of these three structures can become impinged and produce pain.

The three main causes that lead to sub-acromial impingement are:

  1. Poor posture causing the scapula (shoulder-blade) to tip up and forward (also known as a ‘winged’ or ‘elevated’ scapula)
  2. A hooked acromion – that is, excessive bone formation due to trauma (quite rare)
  3. Wear, tear, swelling and or degeneration- from internal structures repetitively rubbing in this space due to occupation or sport.

Most research however has found that the cause of these symptoms are generally the tendon, especially when the injury progresses into tendinopathy.

Symptoms present mostly when you try to perform an overhead activity or exercise, such as swimming freestyle, throwing a ball, or lifting a weight above your head in a PT session!

Shoulder impingement syndrome
Why does sub-acromial impingement develop?

Sub-acromial impingement is a very common condition and seems to affect sedentary people who try to get back to exercise. Given that posture is the most likely cause of this injury, it is best that you start by trying to stretch your pecs, lats and rotator cuff. You can also use a trigger ball or foam roller to improve your mobility.

What to do about it?

If you shoulder pain is disrupting your work, your sleep or your exercise- avoid the cortisone injection and have an Osteopath or Physiotherapist have a closer look to identify the specific causes and contributing factors to your pain. A combination of hands-on treatment, some simple exercises and specific stretches, and possibly some work-place modifications will lead you towards a full recovery- allowing you to get back into the activities you enjoy doing without worrying about pain.