In my post on the anatomy of the IT band I mentioned the band is consistently talked about like it’s a muscle, when in fact it is a band comprised of multiple muscles.
It’s not a muscle; it’s made of muscles.
The rotator cuff is similar.
The rotator cuff is not a muscle; it is a group of muscles.
Specifically, the rotator cuff is made up of the:
-Supraspinatus
-Subscapularis
-Teres minor
-Infraspinatus
These muscles do NOT all perform the same function. In fact, the subscapularis (internal rotator of the humerus) and the infraspinatus / teres minor (external rotators) actually perform opposite functions.
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The distinction between the cuff muscles and their function is a very, very important one to make.
Here is why:
I consistently find people talking about “training the cuff.” Along this vain I’ll read how we all need to train our cuff to stabilize the humerus in the glenoid fossa.
If we are training stability then this implies we have too much mobility, right? Let’s go with that theme and see where it takes us.
Typically, when it comes to the humerus being hypermobile, it’s either in the anterior or superior direction. The humerus travels too far forward or too far upward; too often. And here it’s important to mention a joint is just about always hypermobile in one direction. Not ALL directions. Using the humerus again, the joint may be hypermobile (I guess we can say “lacking stability” for relatability) in the anterior direction but hypomobile (not enough mobility aka “too much stability”) in the posterior direction.

Humeral anterior glide. Right picture is bad, left is better. From: http://www.manualtherapymentor.com
Let’s go with the anterior hypermobility, as this is more common. (For all those who get pain at the bottom of a bench press, humeral anterior glide is why.)
What’s going on with the rotator cuff in anterior glide (a common reason for shoulder pain)
I wrote quite a bit about the muscular imbalances in this issue in Best exercises for the subscapularis, I’m going to use some of the info from that post.
Often times the tight/overactive muscles in this case are pectoralis major and latissimus dorsi. This is because the subscapularis (remember- a cuff muscle) isn’t internally rotating the humerus like it should be. So, other internal rotators, like pec major and the lat, pick up the slack.
The subscapularis also depresses the humeral head. Because the humeral head is shooting so far forward we have a clear indication the subscapularis isn’t depressing the humerus like it should be. (Ah, that humeral stability we’ve been hearing about.) Because of this, the infraspinatus and teres minor pick up the slack as depressors.
One thing I didn’t go over in that post was indicators the infraspinatus and teres minor were overactive. I’ll use a stretch everyone always references: The Sleeper Stretch
Before someone asks, no, I don’t use this stretch, at all. I don’t think Eric (pictured) does anymore either.
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When dealing with the sleeper stretch it’s common for people to let their scapula wing / anteriorly tilt / move, and or humerus glide too far forward, in order for them to get their arm down.
So, many people -rightfully so- mention the need to eliminate these factors, and then you realize how little you can actually internally rotate your arm.
What I never see anyone write about is why, when done correctly, a person suddenly has such little motion. Yeah, yeah, “the posterior capsule is tight, bro.” What about the muscles at play here?!
If we’re internally rotating the humerus that means we’re stretching the external rotators, right? And what externally rotates the humerus? The infraspinatus and teres minor -rotator cuff muscles.
This is why when performing the sleeper stretch properly you suddenly have such little range of motion (some know this as glenohumeral internal rotation deficit (GIRD)): You’re now putting the humeral external rotators on stretch, and they’re tight.
Also, now you know why the scapula tends to wing on people when their arms internally rotate (like in the sleeper stretch). Where do the infraspinatus and teres minor start?
The middle to the medial border of the scapula i.e. These muscles can pull on the humerus AND the scapula.
Thus, so many people who present humeral anterior glide also have scapular winging.
Here’s an example. Notice the right humeral head gliding forward and the right scapula winging. It gets progressively worse as the video goes on:
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Hence, in my subscapularis exercise post I wrote:
Therefore, when strengthening the subscap we want to pick exercises that elicit great activity in the subscap, but don’t elicit much activity in pec major, lat, infraspinatus, and teres minor.
In actuality, part of the shoulder is TOO tight / rigid / stable / whatever, and part of the shoulder is too mobile. Thus, “stabilize the shoulder” is NOT a solution.
Going with this, part of the rotator cuff is too tight / rigid / stable, while part of the cuff is not active enough. Thus, “strengthen the rotator cuff” is NOT a solution.
Because what’s advocated for one muscle of the cuff is contraindicated for another.
This is my long way of saying any declarative statements to the tune of “You need to train your cuff son” is incomplete. And probably said by someone who doesn’t understand what they’re doing.
What direction is unstable? What muscles are long? What muscles are weak? WHICH rotator cuff muscle is long, weak, tight? Etc.
Context, context, context.
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Keshava Raghuveer
February 14, 2013
This has always been the challenge, explaining to clients (and often other trainers!) that the forces acting on a joint to elicit movement have to be BALANCED before movement can occur without dysfunction. What that dysfunction might or might not mean in relation to pain and/or compromised movement is a whole new ball game too!
Part of the problem is with pseudo-scientific sites and the phenomenon I have dubbed “muscle of the week” (no pun intended ;-)). Very often when I train my clients I hear a trainer triumphantly announce things like “If you can’t do X weight on Cuban Press you might as well shoot yourself”.
Now clearly they have seen Poliquin or another strength coach mention the exercise in relation to a specific client and have adopted it as their modus operandi that week to sound smart. Unfortunately they don’t know enough of the functional anatomy to check if there is humeral head migration, anterior tilt of scapula etc. So we have the irony that the very solution to an imagined problem ends up creating the very same problem!
Another muscle I hear doing the rounds now is serratus anterior. 100s of EMGs are flying across the Internet, this is the best exercise, look at the muscle activation readings!!
Sadly in the quest to improve the strength of these muscles, not enough trainers are asking if there is actually no strength issue but rather one of poor motor control. You can strengthen a muscle with all manner of exercises, but if you don’t have an ability to appropriate neuromuscular control of the muscle in question, in relation to a given movement pattern, it might not help your issue.
Excellent post again Mr.Reddy, I have suggested to many of the trainers I hear spouting ‘bro science’ to have a read of your posts as an introduction to help them frame their knowledge of anatomy better. If they can start to ask some of the right questions they might give better answers! The nuances and subtleties of the body are fun to work with if you know what you are doing, sadly science and evidence based assessment of people is still lacking in the trenches of our industry.
You are doing much good work to help, keep going!
Best regards
Keshava
reddyb
February 14, 2013
Great points!
If you don’t mind Keshava, where are you located?
Keshava Raghuveer
February 15, 2013
I am in the process of moving to Vancouver, Canada. I hope to be installed and settled there this year. It’s going to be fun trying to build a new practice and movement centre out there! I currently reside in London, England.
Best regards,
Keshava
reddyb
February 15, 2013
Ah! I LOVE Vancouver. I was there last summer and was absolutely blown away.
Best of luck with everything! I will keep you in mind as I’ve had a good amount of Canadians ask me if I knew anyone in that area.
Hell, if you need an employee let me know. I’ve had moments of seriously contemplating moving there.
Keshava Raghuveer
February 16, 2013
For sure mate! As soon as I am set up there will let you know be great to talk shop and compare notes on movement and a fine ale!
Am in the process of getting my content together to build my website, will let you know once it is up and running.
All the best, speak soon
Kesh
Blake Banks
March 22, 2015
Just curious about ways to go about stretching the right spots, working/fixing movement patterns of the weak spots, and improving overall scapular movement. My right humoral head glides forward during tricep extensions, bicep curls, benching, etc. I notice I would tighten my right rhomboid when it was winged to take up the slack of the subsscapularis (I’m guessing). The side that wings (right) is also the side of my drooped shoulder. Noting pain in the deep part of the bench press, I wouldn’t be able to activate my right pec well either, hence my much larger left one. I try to lower the weight keep my back stable and my shoulders relaxed, elbows in, and sometimes after hard concentration I can get the weight up with a chest pump instead of a front delt forward glided humoral head. I’ve figured out how to keep my scapula from winging by using the SUbscap. But when under pressure from exercise with weights (or remembering to keep it in check with daily posture lol) it always seems to wing and humoral head make its way forward. I have a few videos of doing pushups and other things where it’s obvious I’m not stabilizing correctly more so proving I have a mobility understanding issue. Was curious if I could show you those and maybe you could remedy to the best of your ability? Just trying to get to the potential I know the human body can be. Curse modern sedentary lifestyles. Thanks
Blake, 20
reddyb
March 24, 2015
Hey Blake,
Since you mentioned humeral anterior glide and exercising the biceps, I wrote something about that a couple months ago here: http://b-reddy.org/2015/01/09/training-the-biceps-when-you-have-shoulder-problems/
In terms of looking at you and making specific recommendations, you can take a look at these two options:
-http://b-reddy.org/2014/08/04/phone-video-consultations/
-http://b-reddy.org/2013/06/20/the-remote-client-process/
I’m not sure if you’ve read it already, but there is a lot about winging on the site already as well.
-http://b-reddy.org/tag/scapular-winging/
Blake Banks
March 24, 2015
I’ve watched and read them all. Read most of Evan Osars book on Corrective exercise as well. I’m just struggling fighting the anterior hunoral glide. I do serratus anterior punches with a Thera-band along with a few other gentle exercises as well. I also am getting progressively more adept at correcting my posture, as I like to let my right shoulder go forward, wing, and use my rhomboid to hold in place. Just curious of any thoughts or comments you could give towards me gaining new ground. I also emailed.
Thanks
reddyb
March 25, 2015
Based on the exercises you mentioned, I’d make a good bet you’re doing exercises which are 1) Too heavy and or 2) Too difficult.
Correcting anterior glide during a bench press is extremely hard. Often, a person needs to start with getting rid of anterior glide only moving their own arm. No added resistance.
Blake Banks
March 26, 2015
I see. Ill take a break and give it a shot. When standing with correct posture, I’ve figured out how to activate the Serratis anterior. But that leaves me looking like I’m holding my shoulders wide and awkward. Am I suppose to then pull my shoulders back with the middle or lower trapezius? I know it shouldn’t be a hard pull but I’m conspired on which to use. Also my right humorous sticks forward more so than my left in resting position. Is this from years of doing incorrectly and the ligaments and muscles are just stretched? Should it correct over time?
reddyb
March 27, 2015
Without seeing you, I don’t know about your scapulae. Your shoulders feeling wide and awkward could be a good positioning. It may feel awkward only because you’re not used to it.
For the humeral anterior glide, often a humeral head which sits too far anteriorly is accompanied by a humerus which is held in extension. I go over this in this postural assessment: http://b-reddy.org/2013/02/06/example-of-a-postural-assessment-2/
Patrick Köhler
November 21, 2016
thanks, great 1.
so would you also say the external rotators anterorly pull the humerus?
thanks, patrick
reddyb
November 22, 2016
I wouldn’t phrase it that way.
External rotation of the humerus does cause anterior movement of the humeral head. This is one reason a great way to dislocate a shoulder is to fall out on an abducted and externally rotated arm- the humeral head has already moved (a tad) out of the socket.
You can easily see this yourself. Abduct the arm to 90 degrees, elbow bent to 90 degrees, then do external rotation. After a certain point you’re all but guaranteed to feel pressure into the anterior shoulder. (Place opposite hand on that area and you’ll really feel it.)
But this isn’t exactly the external rotators anteriorly pulling so much as it is how our bones are structured. Perform external rotation but at 0 degrees abduction, and you won’t feel the same anterior pressure at the shoulder.
(Excessive e.g. anterior glide is where problems arise.)
Furthermore, if you think about throwing an object, where the humerus is distracting from the glenoid, then the external rotators can be pulling the humeral head posteriorly.
Patrick Köhler
November 29, 2016
thanks a lot brian! things are now clearer 🙂