I can’t believe we’re already up to 5 parts on this topic! In case you missed it.
Do you guys remember upper crossed syndrome from Part 3? For a refresher look to the left. I like to think of upper crossed syndrome as an example of the most common postural problems. In reality everyone is going to have their own postural variations. Upper crossed syndrome paints a nice picture for understanding what poor posture looks like. It also gives us an understanding of what muscles could be lending to these problems.
So what’s going on with poor posture seen in Upper-Crossed Syndrome? (1)
What gets tight and shortened? (1)
What gets weak and lengthened? (1)
So why do we worry about achieving better posture? Once again it all comes back to the subacromial space, or the room between our humeral head and acromion that when decreased can lead to impingement or “pinching” in the shoulder.
Albeit by a small amount, slouched posture has been shown to significantly decrease subacromial space during elevation of the arms overhead in individuals with rotator cuff disease (2).
As described above, poor posture can be attributed to tight musculature on the front of our chest. If the pectoralis minor becomes tight and shortened it can end up causing scapular winging and scapular anterior tilting. If we recall from part 3, this combination is associated with decreased subacromial space and impingement (3,9).
Decreased subacromial space = more risk for impingement. Seems to be the trend here.
Food for thought: I’m making a huge case for posture and shoulder problems but research shows us that static posture might not be as important as we once thought for impingement patients (4). What seems to be important is decreased dynamic mobility (4). This essentially means that people with impingement and normal pain free individuals have similar static postures at rest. The difference is in their mobility once you ask them to start moving their arms overhead.
My issue with having poor static posture is that over time it will definitely lead to decreased active mobility over time. We need to nip this in the bud.
So what causes poor posture?
In order to get oxygen into our body we need to fill the lungs with air throughout the day. We end up taking somewhere between 15,000 to 20,000 breaths every day. Normally, the fatigue resistant diaphragm is the predominant muscle of choice in order to get the job done. When we engage in strenuous exercise we start to call in secondary breathing muscles to expand our rib cage and pull extra air in to help feed more oxygen to hungry muscles.
While traditional quiet breathing (breathing at rest) is supposed to use the diaphragm predominantly to accomplish respiration, research shows us that healthy individuals also get a good deal of thoracic movement in quiet breathing (6). Using a pattern of breathing that causes more movement from the ribcage is a sign that the accessory breathing muscles are overworking when they’re supposed to be quiet.
Accessory breathing muscles are not as fatigue resistant as the diaphragm and they’re likely to become hypertrophied and shortened with excessive use.
A list of the accessory breathing muscles – specifically muscles of inhalation (7):
If the bolded muscles become shortened they’re going to contribute directly to the postural faults seen in upper crossed syndrome.
The pec minor can cause scapular winging. When the pecs and lats get shortened they’ll produce internal rotation of the shoulder.
Remember that in part 1, internal rotation of the shoulder is usually a provocative position for pain in individuals with impingement. This is due to the greater tuberosity of the humerus banging up against the acromion when we raise our arms overhead (8). If we’ve got increased gleno-humeral (shoulder joint) internal rotation during overhead movements we run the risk of impinging structures in the subacromial space. (Another case for improving your technique when lifting) This is yet another area that must be addressed in order to achieve normal motion at the shoulder.
So these are the basics of shoulder impingement! I hope you guys enjoyed the article series thus far. In the future I plan on putting together strategies for rehabbing subacromial impingement.
Sitting here writing is terrible for my posture,
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1. Page, P., Frank, C. C., & Lardner, R. (2010). Assessment and treatment of muscle imbalances the janda approach. (pp. 195-207). Champaigne, IL: Human Kinetics.
2. Kalra, N., Seitz, A., Douglas Boardman, N., & Michener, L. (2010). Effect of posture on acromiohumeral distance with arm elevation in subjects with and without rotator cuff disease using ultrasonography.Journal of Orthopaedic and Sports Physical Therapy, 40(10), Retrieved from http://www.jospt.org/issues/articleID.2473,type.2/article_detail.asp
3. Ludewig, P., & Reynolds , J. (2009). The association of scapular kinematics and glenohumeral joint pathologies. Journal of Orthopaedic and Sports Physical Therapy, 39(2), 90-104. Retrieved from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2730194/pdf/nihms-114923.pdf
4. McClure, P., Michener, L., & Karduna, A. (2006). Shoulder function and 3-dimensional scapular kinematics in people with and without shoulder impingement syndrome. Physical Therapy, 86(8), 1075-1090. Retrieved from http://ptjournal.apta.org/content/86/8/1075.full
5. Dael, N., Mortillaro, M., & Scherer, K. (2012). Emotion expression in body action and posture. Emotion,12(5), 1085-1101. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/22059517
6. Kaneko, H. (2012). Breathing movements of the chest and abdominal wall in healthy subjects. Respiratory Care, 57(9), 1442-1451. Retrieved from http://rc.rcjournal.com/content/57/9/1442.abstract
7. Clarkson, H: Musculoskeletal Assessment – Joint ROM and Manual Muscle Strength. 2nd ed. Philadelphia: Lippincott Williams & Wilkins, 2000.
8. Brown DP, Freeman ED, Cuccurullo S, et al. Shoulder Disorders. In: Cuccurullo S, editor. Physical Medicine and Rehabilitation Board Review. New York: Demos Medical Publishing; 2004. Available from: http://www.ncbi.nlm.nih.gov/books/NBK27311/
9. Escamilla, R., Yamashiro, K., Paulos, L., & Andrews, J. (2009). Shoulder muscle activity and function in common shoulder rehabilitation exercises. Sports Medicine, 39(8), 663-685. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/19769415
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Shoulder Impingement: Part 3 – The Shoulder Blade’s Role in Impingement
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