Most people will hurt their shoulder at some point. In any given year, 20 to 30 per cent of the population will experience some shoulder pain. In my physiotherapy practice, shoulder pain and injury account for about 30 per cent of the caseload.
Excessive shoulder mobility is a common contributor to pain and injury. The ample mobility in our shoulders allows us to do some amazing things with our arms, but doing those things without injury requires a certain muscular control for stability. The mobility and stability requirements of the shoulder are forever at odds.
Some people's shoulders have more mobility than others. It is estimated that 30 to 50 per cent of people have some degree of looseness, but this number is higher in people experiencing shoulder pain. Looseness doesn't have to be an issue if you move well, but when this looseness of the joint starts to cause pain, it is called instability.
Instability is a clinical diagnosis, meaning it can't be seen with diagnostic imaging such as ultrasound and MRI. Instead, the presence and degree of instability are identified by a history and some carefully performed hands-on tests.
Shoulder blade position and movement are also difficult to observe on diagnostic imaging. The shoulder blade "floats" on the rib cage with only muscular attachments. The flexibility and strength of these muscles have to be balanced to allow the optimal movement relationship between the arm and the shoulder blade.
An impaired movement relationship and instability are factors behind most shoulder injuries, including impingement – another common clinical diagnosis that is difficult to appreciate with imaging. Impingement syndrome is pinching or entrapment of the important rotator cuff tendons, small muscles meant to stabilize the shoulder joint. If they don't do a good job of stabilizing the joint, the tendons get impinged. That's when the rotator cuff gets damaged.
If you undergo a diagnostic ultrasound or an MRI, you might receive a diagnosis of rotator cuff tendinitis or bursitis, but that does not describe why the problem arose or how to fix it and prevent it from happening again.
How you move is more important than whether there's looseness in the shoulder or even some rotator cuff damage. Because most of us don't spend that much time performing overhead arm movements, our technique may be flawed. If certain shoulder movements hurt at some times and not others, it may be that we're not that good at them, our performance varies or we fatigue with activity.
Many people report occasional clicking in the shoulder and pain with certain movements. This is a sign of excessive movement that's poorly controlled. You should never experience clicking or pain. The more strenuous the activity, the more important your technique becomes. This applies not only to overhead sports such as swimming and tennis but to everyday movements like reaching, lifting and carrying.
The difference between good and bad technique is subtle, the analysis of which requires a keen eye, but here is the gist of it. The shoulder is a ball-and-socket joint, with a relatively large ball and a smaller flat socket, analogous to a golf ball on a tee. Throughout overhead arm movement, the ball and socket need to be centred. Many people, especially those with loose shoulders, allow the ball to sit forward on the socket, where impingement happens more easily. To centre the ball on the socket, you need to pull the ball back very slightly without pulling back the shoulder blade. Usually people learn this technique fairly quickly, but incorporating it into everyday life requires practice.
Optimal shoulder blade movement also takes practice. As you raise the arm, the shoulder blade shouldn't be pulled too far back nor pressed too far forward. It shouldn't be held down nor elevated excessively. There's a sweet spot in the middle where the shoulder blade rises a few centimetres throughout full overhead arm movement. When this happens, the shoulder blade tilts backward a bit and rotates outward about one degree for every two degrees that the upper arm moves.
The right movement can have an enormous impact on symptoms. It is not uncommon for someone with shoulder pain from instability, impingement and rotator cuff tendinitis to have nearly full, pain-free overhead arm movement after a single physiotherapy session where they practise the correct technique. But it can take weeks of practice to master this movement during everyday activities.
Your physiotherapist can demonstrate a host of stretching and strengthening exercises to help facilitate this good movement. If you have shoulder pain, this type of treatment can make all the difference in getting you back to your favourite activities. The correct movement technique can also help prevent shoulder injuries and optimize athletic performance.
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Justin Vanderleest is a Toronto-based physiotherapist at Athlete's Care and LiveActive Sport Medicine. He has a Master's of Clinical Science in Advanced Orthopaedics and Manipulation from the University of Western Ontario. He is a Fellow of the Canadian Academy of Manipulative Physical Therapists. An elite squash player and former national champion sprint canoeist, Vanderleest has developed special interests in training programs and injury prevention. You can follow him on Twitter @JDvanderLeest