The shoulder is an amazing joint, capable of great things…when it is all functioning properly!
The shoulder is comprised of 4 joints – the sternoclavicular, the acromioclavicular, the scapulothoracic(ScTJ) and the glenohumeral (GHJ). The GHJ is quite unstable due to its lack of bony stability but is held in place by numerous ligaments, the joint capsule and rotator cuff and scapular muscles.
Normal shoulder ROM is as follows:
Flexion 180 degrees (the top of a push press)
Extension 40-60 degrees (lifting your arm straight behind you)
Abduction 180 degrees (lifting your arm out to the side)
Internal rotation 60-70 degrees (rotating the arm in towards the middle)*
External rotation 80-100 degrees (rotating the arm outwards)*
* tested with the arm abducted and elbow flexed to 90 degrees
In Crossfit (and in normal day to day life) our shoulders also need to be able to hit combined ROM – for example reaching for a seat belt involves shoulder abduction and external rotation, putting your wallet in your back pocket involves shoulder extension and internal rotation.
Lets take a look at the shoulder position in an overhead squat – full shoulder flexion, abduction and external rotation. The overhead squat is a demanding movement that requires not only good mobility and stability at the shoulder joint, but a mobile thoracic spine and hips, plus great core control. Take a look at the two photos below, one of which demonstrates a good overhead position.
 |
|
Which one would you rather look like?
I often see people complaining of shoulder pain and they are usually missing some degree of shoulder internal and/or external rotation. Lack of external rotation at the shoulders causes you to look like the guy on the right (he’s probably also missing full range shoulder flexion and some degree of thoracic extension. I won’t get started on the hips…)
Try the Apley Scratch test to see if you have adequate shoulder rotation: 
Apley scratch test. The patient attempts to touch the opposite scapula to test range of motion of the shoulder. (Left) Testing abduction and external rotation. (Right) Testing adduction and internal rotation.
|