On a daily basis I have “the posture talk.” It’s almost a simultaneous reaction from my patients to sit up straighter, pull their shoulders back, and look about six inches taller. We all know what good posture looks like, but why do nearly all fail to follow through? Countless studies, articles, and presentations are given each year on the importance of good posture. So why do we continue to slouch, hunch, and slide further down in our chairs?
Poor posture is almost always linked to the neck and back; however, the negative effects reach further than you think. There’s no doubt that poor sitting posture plays a huge role in protecting your neck and back, but the influence to the shoulder is often overlooked. Sitting in a slouched position causes the upper back to bend forward, ultimately changing the position of the shoulder blades as they tip forward and wrap outwards to accommodate a slouch. Over time a slouch will alter how our shoulder blades move.
Proper shoulder blade movement is critical to shoulder motion, strength, and function. For every two degrees of shoulder movement the shoulder blade contributes one degree of movement. This is known as “scapular humeral rhythm.”
1. Improper Movement Causing Injury
Improper movement at the shoulder blade movement due to tightness and weakness can often result injury at the rotator cuff. Truthfully, a majority of shoulder injuries are gradual onset and free of a specific mechanism for injury. Overtime, poor movement between the shoulder blade, shoulder, and spine often causes a “pinching” of the rotator cuff against a bony shelf (the acromion), also known as shoulder impingement. Those with chronically poor movement are often subjected to accelerated “wear and tear,” tendonitis, or tendinosis.
Unfortunately, prolonged sitting has become an occupational necessity . Millions of people are adapting to a sitting position that directly carries over into non-sitting positions. A slouched sitting posture misaligns the shoulder blade, throwing the “scapulohumeral rhythm” off before movement is initiated. One study reported that with healthy subjects placed into a slouched position shoulder movement to the side and overhead decreased by nearly 15%. (1)
2. Less Motion Due to Tightness
Sitting slouched also effects the flexibility of the muscles around the shoulder, chest, and upper back. Most patients nod in agreement when I ask if they find their shoulders up near their ears as the stress of the day wears on. This common, seemingly harmless posture tightens the upper trapezius muscle over time. Another study showed that people with shoulder pain had increased upper trapezius activation with overhead activity compared to their pain free peers (2). This is a place to stop and note that doing shoulder shrug exercises in the gym are not a great idea.
3. Loss of Strength / Too Loose
While some muscles tighten in poor posture, others will become too stretched leading to muscle imbalance. Our muscle strength will vary depending on the position which it is located. A shortened (tight) or lengthened (loose) muscle is unable to reproduce the same force compared to the optimal position. By slouching many of the muscles in the middle of the back are placed on stretch, while the front of the chest is placed on slack. Overtime muscle imbalance builds and often leads to muscle pain that has no specific cause or incident of injury.
When in doubt, it’s always best to do three things: 1. Practice good posture 2. Stretch the chest wall and 3. Strengthen your mid back.
Next time you are sitting at your desk and catch yourself hunched over the keyboard, with your shoulders neighboring your ears take the time to sit back and straighten up. While maintaining good posture throughout an eight-hour work day is seemingly impossible, awareness is the first step. With each correction of posture the body is able to “reset”. Good posture won’t happen overnight; however, practice makes perfect. Hopefully you finish reading this sentence sitting up straight, with your shoulders back, and upper shoulders relaxed!
1. Kebaetse, Maikutlo, Phillip McClure, and Neal Pratt. “Thoracic Position Effect on Shoulder Range of Motion, Strength, and Three-Dimensional Scapular Kinematics.” Archive of Physical Medicine Rehabilitation 80 (1999):
2. Ludewig, Paula, and Thomas Cook. “Alterations in Shoulder Kinematics and Associated Muscle Activity in People With Symptoms of Shoulder Impingement.” Journal of the American Physical Therapy Association80.3 (n.d.): 276-91. Web.