The Rotator Cuff

What is the rotator cuff?

A group of muscles surrounding the shoulder joint:

Supraspinatus:

Location: Supraspinous fossa of scapula (shoulder blade) to greater tubercle of humerus (upper arm bone).

Basic action: Assists deltoid in abduction (out to the side movement) of the humerus.

Infraspinatus:

Location: Infraspinous fossa of the scapula to greater tubercle of the humerus.

Basic action: Externally rotates (turns out) the humerus.

Teres Minor:

Location: Lateral border of the scapula to greater tubercle of the humerus.

Basic action: Externally rotates the humerus.

Subscapularis:

Location: Subscapular fossa of the scapula to lesser tubercle of the humerus

Basic action: Internally rotates (turns in) the humerus.

However these basic actions don’t occur in function as the cuff work together to do something very different!

So what does the rotator cuff actually do?

Aids movement of the glenohumeral joint (shoulder joint)

Compression of the humerus on the glenoid (keeping it tight in the socket)

Centring the humerus on the glenoid and translation control (keeping it in the centre of the socket)

Sensorimotor control & proprioception: There are mechanoreceptors (detecting sensors for movement) in many of the anatomical structures of the shoulder that feedback and feed forward to stabilise and control the joint.

What is the relevance to everyday people?

Shoulder pain is one of the most common musculoskeletal conditions accounting for between 7 -26% of G.P consultations in the UK. The rotator cuff is something that is targeted to help people suffering with shoulder problems.

It is often considered that muscle imbalance can cause abnormal joint alignment & shearing forces causing osteoarthritis to develop in later life (Kisner & Colby, 1996).

Scapular control and coupled rotator cuff activation is vital to normal shoulder function (Kilber et al 2001)

Many therapists try to target the rotator cuff but is this really possible?

This research with EMG (electromyography), which shows the electrical muscle activity, may shed some light on this issue:

Performing external rotations in side lying, it was found that the greatest amount of EMG activity was found in the infraspinatus muscle, which was 62% of a maximum contraction & teres minor was 67% (Reinold et al 2004).

The EMG in prone horizontal abduction at 100 degrees with full external rotation showed that supraspinatus was 82% but middle deltoid was 87% & posterior deltoid was 88% (Reinold et al 2004)

Kelly et al 1996 found the full can resisted scaption at 90 degrees (see first diagram below) produced the most supraspinatus contraction with the least co-contraction of infraspinatus. For subscapularis the Gerber push (see second diagram below) with force test gained the most activation with the least co-contraction of Pecs and lats.

This suggests you can bias the muscles but you cannot isolate them.

The next issue is: Does targeting the rotator cuff improve pain and function of patients?

What does the evidence say?

For:

Scapulohumeral (ball and socket of shoulder) and Scapulothoracic (shoulder blade to rib cage) rhythmic stabilisation training using closed kinetic chain (Position of an arm or leg where the distal (furthest from mid line part) segment of the limb is fixed. In this case the hand is on a surface.)

Strengthening using lateral (external) and medial (internal) rotation with the elbow at the side and progressing resistance improves rotator cuff strength and function (Morrison et al 1997)

Closed chain axial loading exercises are the primary means of early shoulder rehab & functional rehab protocols (Kilber et al 2001)

Functional shoulder rehab: Activations & joint motions follow a proximal-to-distal (close to mid line-to-furthest from mid line) pathway along the kinetic chain (body segments) (Kilber et al 2001)

Muscles around the shoulder function in an integrated fashion and should be rehabilitated in integrated patterns (Kilber et al 2001)

Stretching & scapular motor control training was effective in the treatment of shoulder impingement syndrome (Struyf et al 2013) (see blog article: http://mathewhawkesphysiotherapy.blogspot.co.uk/2013/06/shoulder-impingement-syndrome-sis.html )

Against:

There was no evidence for scapula stabilisation exercises in shoulder impingement syndrome (Faber et al 2006)

So what should we do then?

The consensus is that you should assess the person’s abilities wider than that of the shoulder!

Look at things such as single leg balance, single leg squat, weight transference, lunging etc. This is because faults with movement earlier in the kinetic chain will create a change in movement and force further up (shoulder) through compensation.

Also it is good to assess Core control & Thoracic (mid back) flexibility as these will influence the shoulder:

Sobel et al 2009 found that 40% of shoulder patients had thoracic and rib dysfunction.

Even though we need to train for function with our rehabilitation exercises, some people are non-functional in the early stages so in this case it is sensible to start with less functional exercises specific to the shoulder. But remember if you have seen any abnormal movement patterns in other areas of the body then you will need to target these first otherwise the shoulder problem could persist or come back again in the future.

For example if you are a swimmer and have poor thoracic rotation and extension then this is the place to start, by improving the flexibility and control of this first. When this improves, begin to target the shoulder.

Specifically these exercises are good early ones to do:

Stabilisation exercises:

Stabilisation is sitting: 

Stabilisation in standing: 

Stabilisation in 4 point kneeling: 

Stabilisation with a ball:

Early strengthening:

Lateral rotation: 

Medial rotation: 

Intermediate strengthening exercises:

Flexion wall slides:
With something that slides between your hand and a wall or mirror, push to add compression with your hand and gently slide your hand up and down the wall or mirror.

Through range looped exercise band flexion:

Through range looped exercise band flexion with a step up:
The same as above but as you elevate your arms, step up a step with your right leg until your right knee is straight, the knee should become straight at the same time that the arms reach the top. Then without putting the left foot onto the step (so you’re standing on 1 leg) lower back down and bring your arms down at the same time and touch down with your right foot. Repeat with the left leg. (see below)

Horizontal abduction with lateral rotation: 

Keeping the arm horizontal, move it from front to back with the thumb pointing up with exercise band resistance.

Prone Y arm lifts:

Advanced functional strengthening:

This will depend on the activities of the individual. For example a sport person who throws will train the motions that occur in that action. For example:

Attach an exercise band at shoulder height on the non-throwing side of your body. Tie a loop into it and loop it around your throwing-hand. Next with correct throwing technique start to perform a slow controlled throwing motion, which involves the movements of the lower limb and trunk.

So the advanced rehabilitation exercises take a little imagination. The progression of these types of exercises should be as follows:

Simple to complex

Slow to fast

Static to dynamic

Programmed to random

So is there anything else that might work too?

An exercise programme was beneficial with manual therapy in shoulder impingement syndrome (Faber et al 2006)

Mobilisation of the cervical spine (neck): McClatchie et al 2009 found performing cervical side glides decreased shoulder pain and increased shoulder abduction range of movement.

Thoracic Manipulation: Boyles et al 2009 found that 48 hours after the manipulation all testing of the shoulder had improved.

Kinesio tape & an exercise program are more effective than the exercise program alone in shoulder impingement syndrome (Simsek et al 2013)

So as you can see the rotator cuff isn’t the be all and end all. It’s just more complicated than that!

Think BIG!!!

If you need any further information or would like to book an appointment then call Hawkes Physiotherapy on 01782 771861 or 07866195914

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