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Protect the force couples

'Green theraband external rotations' has been the butt of many a joke and flippant comment in the strength and conditioning, personal training and even sometimes, rehabilitation worlds.

People mock it perhaps because it's low intensity, it's a bit boring and most likely because they question whether it is of any value.

Still, the majority of people who have had a shoulder injury have probably been prescribed this exercise in some form. And for good reason.

I could actually give you about five good reasons but I'm going to focus on the one thing that encompasses them all.

Creating the conditions for optimal movement

Many people say the shoulder is complicated. The reality is, it's more than that. Complicated systems can be deconstructed to their individual components and the mechanics can be fully understood. A Swiss watch is complicated.

The human movement system is complex. That meaning it is made up of multiple systems that are interactive and interdependent.

Aristotle put it simply: 'The whole is more than the sum of its parts'.

So what has this got to do with green therabands?

The design of the shoulder means that it has more degrees of freedom, or movement options, than any other joint in the body.

The brain therefore has many ways it can achieve an outcome. If the most optimal option A isn't available for whatever reason, it will go to option B, then C and so on. Basically the brain will find a way to help you get into the position or execute the movement that you're asking it to. Whether that is optimal or not is a different question.


To help simplify some of the complexity around the shoulder, we’re going to talk about force couples.

A force couple is defined as two equal forces acting in opposite directions to rotate a part about its axis of motion.

There are two primary force couples that have particular relevance to the strength and conditioning coach and personal trainer.

By knowing what they are and how to train in a way that optimises them, you go a long way to making option A available to the brain and therefore reducing pain and instability. Furthermore you pave the way for greater tolerance of volume and intensity which leads to more opportunity for progressives overload. And it is here that we get everything we need.



From a very simplistic point of view, this force couple is trying to keep the ball (the humeral head) on the socket (glenoid fossa on the scapula).

The rotator cuff is working to control the position of the humeral head on the socket as the shoulder moves through the desired range of motion and at the desired intensity.

This is where the green theraband comes in.

The infraspinatus and teres minor are 2 muscles that make up the rotator cuff. They are both extremely important in creating external rotation.

Through most training practices we'll generally see an increase in internal rotation strength whilst, unless we target it specifically, external rotation strength get's less 'specific' stimulus.

An imbalance in the ratio of external rotation to internal rotation strength is common in many grumbling shoulder problems. And many grumbling shoulder problems can be improved by increasing external rotation strength and therefore optimising the position of the ball on the socket.



With the rotator cuff keeping the ball on the socket, we also need to think about keeping the socket on the ball. That being the role of the musculature acting on the scapular.

As you go into an overhead position you need the serratus anterior, lower and upper trapezius to upwardly rotate the scapula. I see so many people who have sub-optimal scapulo-humeral rhythm and control which is contributing to the problems they are experiencing.

The other component to consider is the relation between the scapula and the ribcage. As the scapula moves in response to the position of the upper limb, its movement is guided by the ribcage. Think about the train (scapula) riding on the track (ribcage).

A scapula and ribcage aren't positioned optimally can be a contributing factor to shoulder performance limitations.

Exercises using low loads, sometimes with a theraband, can be a very effective way of re-educating more optimal movement patterns and strengthening the serrates anterior and lower trapezius.


So here is the take away.

If you protect the force couples you lay the foundations for everything else you want from a strength training and performance perspective.

For most people, you can do this by:

1. Regularly including specific rotator cuff exercises in your movement preparation. Try the side lying external rotation shown below. Aim for 12 - 20 reps on each side with a 4 second eccentric tempo.

The rotator cuff responds well to being trained in different positions so try the knee supported option too.

2. Giving attention to how you are moving can be a game changer for a lot of people.

There are a number of very good activation exercises you can use for the serratus anterior and lower trapezius but try starting with an inverted kettlebell press. Rather than smashing out reps just to get the set complete, slow down and think about how you're moving from A to B.

Build an awareness of what it's like to consciously push your hand up with the scapula and let it move up and around the ribcage instead of holding it 'back and down'.

Side Lying External Rotation

We're going to give the rotator cuff a little bit of special attention, particularly the external rotators with this side lying external rotation movement.

Inverted Kettlebell Press

The inverted kettlebell shoulder press is a favourite when it comes to shoulder stability. Really simple, by taking the kettlebell upside down the shoulder has to think about delivering the hand and the elbow through a good movement pattern to maintain stability.


Maybe it's time to stop making fun of green theraband external rotations.

Improving the function of the force couples is a very effective way to create more optimal shoulder movement and better levels of performance, and this type of exercise is part of that process.

Is it the end game? No.

But it is a cornerstone of being able to consistently push the intensity you need to get bigger, stronger, faster or more explosive.

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