Exercise Spotlight - The External Rotation; Maryland Personal Trainer

This week's exercise is the external rotation, depicted in the video below:





Targeted musculature: Teres minor, infraspinatus.




Why: Increased performance!


How the External Rotation Can Increase Performance

Despite the over-prescription of the external rotation in the physical therapy arena, external rotations are one of the most useful (and overlooked) exercises for healthy people participating in regular resistance training.

The pectoralis major and the latissimus dorsi (yes linking to wikipedia) attach to the humerus in such a way that when they contract, they create a torque of internal rotation around the humerus. In simpler terms, when doing a bench press and the chest contracts to press the bar up, the chest musculature is also "twisting" the humerus.

To prevent the humerus from over rotating, the external rotators must contract in conjunction with the chest and back in order to stabilize the glenohumeral (shoulder) joint. If the pectoralis major's capacity to produce internal rotation during a bench press exceeds the ability of the external rotators to produce a counteracting force, 2 things could happen:

1. Very rarely, injury could result
2. Much more commonly, the brain prevents the pecs from overcontracting. This leads to less than optimal performance!

So, in order to prevent this from happening, add some external rotations to your program!

Variations

There are multiple ways to do the external rotation. As depicted in the video above, cables offer an excellent choice. Dumbbells, small weight plates, and bands can also be used. Additionally, as I wrote about in the tempo article, tempo can be added to the external rotation to increase difficulty and in some cases specificity.

Furthermore, changing the amount of shoulder abduction can change which of the external rotators is recruited (1). So, it can be useful to incorporate a variety of shoulder positions, such as the arm against the body and the arm fully abducted. A video of an external rotation with the arm against the body is shown at the top of the page. A video of an external rotation with the shoulder abducted can be found below:




Brief Rant on the History of the External Rotation

The external rotation is a popular physical therapy exercise targeting the infraspinatus and teres minor muscles. In addition to externally rotating the humerus, the teres minor and infraspinatus also depress the head of the humerus. This increases the amount of space below the acromion, theoretically relieving any impingement on the supraspinatus tendon. Since a lot of shoulder pain is simply written off as "supraspinatus tendinitis", external rotations are commonly prescribed to relieve shoulder pain. If you are having trouble visualizing this process, this journal article, has some great pictures on page 4 that show typical a "shoulder impingement".

Occasionally, this is effective, but the fact of the matter is that the glenohumeral joint is extremely complicated and nearly the entirety of the upper body musculature is involved in its stabilization either directly or indirectly (by acting on the scapula or humerus). Additionally, the external rotators end up pulling the head of the humerus forward in the socket when they contract, which can cause pain in and of itself.

In short, if you end up at a physical therapist's office for shoulder pain and they give you a band and tell you all that you need is external rotations, run the other way! As a personal trainer, I have worked with far too many clients who came right from a physical therapy clinic with that exact unfortunate experience.

Conclusion

If your bench press has been stagnant, try adding external rotations to your program. If you already incorporate them, try a variety of angles. If you have not used this exercise regularly in your training, you should notice a difference in your pressing strength within a few weeks!



References

Poliquin, C. (1997). The Poliquin Principles. Dayton Publishers & Writers Group.