In last week’s post we spoke about the 1st 4 reasons why people’s shoulders get hurt in the gym.
Now, when we’re looking for bulletproof shoulders we need to tackle shoulder health from a variety of angles. These first 4 concepts are incredibly important to consider. Next we’ll talk a few more reasons why shoulders get hurt in the gym.
5. Lack of Mobility
6. Lack of Strength
Let’s tackle these shall we?
Now, I think when people see this one they’re gonna think, “well, duh. Mobility is super important” However, I don’t think most people grasp where and why mobility is important. I also don’t think we’re fully promoting mobility in the safest way and we might be causing problems by mobilizing too much in some individuals.
In the X-ray to the left you’ll see that the contact area between the ball and socket is pretty small. You’ve probably heard the shoulder joint analogy of a golfball on a tee as opposed to a ball and socket. I’d have to agree there. Now, we’ve got a few structures that help to deepen the socket and stabilize the joint. The two major ones are the labrum and the shoulder capsule. On top of that the rotator cuff surrounds the ball portion of the socket to help keep the ball centered and keep our shoulders healthy and happy.
So far it seems like the shoulder joint needs mostly stability to stay healthy given the anatomy. So why the mobility?
Well for 1, mobility is needed for proficiency in certain positions. If we lack mobility within the shoulder complex we might not be able to get into a solid overhead position for jerks, handstands, pull-ups and overhead press. We also need adequate shoulder extension range of motion to get into a deep dip position and adequate shoulder internal rotation motion to have proper bar path during snatches.
Now, when we lack range of motion we end up in a compensated position. So in the pull-up for example if we lack full overhead motion from tight lats, we end up internally rotating at the shoulder joint when hanging from a bar or rings. When it comes to catching a snatch, tight pecs or lats can do the same. This can cause premature approximation of the greater tuberosity (boney bump on the humerus where multiple muscles attach) and the acromion compressing the rotator cuff.
The same thing can happen in the bottom of a dip. If we lack mobility to get low enough we’ll substitute thoracic flexion, shoulder internal rotation and scapular anterior tilt to accomplish the task.
Why is this bad? Well, for a few reasons. Certain movements of the shoulder blade and thoracic spine increase subacromial space during exercise and reduce compression of the rotator cuff. Check out my article series on shoulder impingement for a refresher on why this is important. Our goal is to minimize compression of these important structures as we train.
Thoracic extension, scapular posterior tilt, scapular external rotation and scapular upward rotation all increase the subacromial space. Check out the images below for an idea of what these movements are:
As much as we can we want to promote these movements during exercise to keep our shoulders happy.
If we’re training in compensated positions we’re probably placing increased stress (compression mainly) on the subacromial contents:
This is one way that having decreased mobility can lead to increased stress on the shoulder.
Now, the other point that Dave Tilley from shiftmovementscience.com talks about frequently is that when we lack mobility of some of the muscular structures surrounding the shoulder joint (Lats, teres major, pecs, delts) we can make up for some of that deficit with mobility from not only the shoulder blade but also from the shoulder capsule.
If the shoulder capsule is making up for a lack of mobility elsewhere the shoulder capsule can begin to stretch and we can start getting capsular laxity over time. This may leave us open to a less stable joint.
Now, some people have more or less inherent stability of the shoulder joint. Some people are more naturally lax and the last thing they need is more mobility of the shoulder joint. That’s why we need a thorough assessment of the shoulder joint (specifically shoulder capsular laxity assessment and/or potentially something like a beighton scale) before we just start shot gunning techniques to improve mobility. Check out my super in depth assessment and treatment video for overhead mobility in my Online Mentoring Group Insiders
Keep in mind that some people may lack shoulder mobility but their limitation is not coming from a capsular origin, but a muscular origin. If we start stretching that shoulder joint we may be exacerbating the issue.
These folks may need more foam rolling as an intervention in order to gain muscular mobility without stretching the shoulder capsule.
So to recap. A lack of shoulder mobility can lead to:
Obviously all good reasons to improve your mobility. Now, let’s talk strength…
So what’s interesting about a lack of mobility is that a lack of strength can cause the same exact problems. This is the exact reason why we need to throughly assess our athletes and know the difference between when someone has a mobility issues vs. when someone has a strength issue.
Let’s use a dip as an example to show how decreased strength can lead to shoulder problems.
In the bottom position of a dip if we lack extension range of motion in the shoulder joint then we’ll compensate with thoracic flexion, scapular anterior tilt and some internal rotation of the shoulder joint to get into a deep dip position. We already spoke about how this can increase the stress on the shoulder.
If I have an athlete who purely lacks strength in the bottom of the dip (without mobility restrictions) the same compensations will show up. I believe 2 things are occurring which drive this.
1. The Body Relying on Passive Structures to Gain Stability and Strength
When in the bottom position of a dip, the shoulder is in close to end range extension. Extension of the shoulder joint also promotes an anterior force on the front of the shoulder. There is also a large anterior force coming from the deltoid’s pull on the shoulder joint. The shoulder capsule normally counters this motion to help keep the ball centered in the socket.
The shoulder joint can also rely partly on the shoulder capsule for stability. For an athlete that lacks the strength coming from the major muscular movers (triceps, pectorals, deltoids) they can pretty easily rely on the shoulder capsule to gain a mechanical advantage.
If you have an athlete who is already fairly lax they’re probably getting more motion within the ball and socket joint. This may be causing more compression of the structures in the front of the shoulder. On the flip side of the coin if you take an athlete who is not lax and have them rely on passive structures in the front of the shoulder they may be creating more capsular laxity over time. As we discussed earlier having more motion within the shoulder joint is probably not a good thing and could be contributing to things like rotator cuff and labral tears.
2. The Body Finding More Optimal Length / Tension Relationships of the Muscles
Muscles are strongest when they are in a an optimal length tension relationship. What this means is that a muscle is going to weakest when it is either fully stretched or fully shortened. A muscle in the mid-range of stretch is going to be strongest. Think about how difficult full range of motion dips are compared to a partial range. The pecs, delts and triceps are strongest in a partial range and get progressively weaker as we descend further and further into a dip.
Because of this weakness we end up with some funky compensations as we descend deeper into a dip.
3. The Body Gaining Mechanical Advantage by Moving Through Different Joints
If you have an athlete who isn’t strong enough to get into the bottom of a dip then they’ll sacrifice shoulder extension with thoracic flexion and scapular anterior tilt. Basically the shoulder isn’t strong enough to get into a deep dip position (full shoulder extension) so they aren’t moving from the right places to complete the rep. Ultimately your body will find another way to get into that deep dip position and accomplish the rep.
I’m sure you’ve seen the athlete that hits the bottom of the dip with the shoulders forward and upper back rounded and then reverses the motion by aggressively extending the spine. You’re watching an athlete who lacks the strength and or endurance to perform dips properly. Because of this they end up trying to drive the movement through the shoulder blades and spine.
These compensated positions are going to compress the sub-acromial contents and increase stress on the shoulder capsule. There you have it! Part 2 complete. Stayed tuned for next installment when we talk specific exercise technique that leads to shoulder injury in the gym and how to fix it.
In case you haven’t realized it, I’ve been on a shoulder kick lately. This is because Dr. Dave Tilley from shiftmovementscience.com and myself have made a big new shoulder product to help physical therapists, coaches and athletes get out of shoulder pain, back to level high levels of performance and to stay pain free for the long run.
Dan Pope DPT, OCS, CSCS, CF L1
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