It seems that shoulder injuries are one of the most prevalent ailments among the average working adult. Interestingly, non-physical work has also produced a vast number of the shoulder injury cases that have come across my desk. These injuries can be as painful and disruptive as lower back pain and should be treated with a similar amount of fervour.
There are many differing types of shoulder injury, each of which with varying grades of severity. Some need surgical intervention, others require passive therapy and a large proportion benefit from active therapy. If you suffer a shoulder injury, the first step (always) is to get the injury properly diagnosed. Yes, that means seeing a GP or a specialist and requesting diagnostic imaging. I’ve seen many cases of delayed recovery as a result of misdiagnosis or underdiagnosis. How can it be treated if the actual injury is unknown?
The aim of this post is focused on the prevention of shoulder injuries. The issue is not in the recovery, as most shoulder injuries if treated in a timely and efficient manner by a health professional can recover to normal fairly quickly. The question I ask is why are so many people injuring their shoulders? How can we prevent the large incidence of these injuries.

Anatomy

The most commonly injured muscles are those that we collectively refer to as the “rotator cuff” muscles. These are the supraspinatus, infraspinatus, subscapularis and teres minor muscles. Of these, the supraspinatus is usually the most vulnerable as it is the main controller of overhead movements.
The shoulder joint is a ball and socket joint (like the hip) but with these muscles forming the “socket.” In the hip, the socket is formed by bone, in the shoulder it is formed by soft tissue. Rotator cuff injury is one of the primary ways shoulder injury occurs.
Long term shoulder stability comes from muscular endurance and strength.
There are also a large number of muscles acting on the shoulder joint including: Latissimus dorsi, teres major, Long head of biceps/triceps, trapezius, deltoid, rhomboid, pectoral muscles, levator scapulae. The harmony of these muscles is vital for shoulder health. If, for example, a person has overactive traps, their shoulders will elevate too early causing the system to be stressed more than required.
In addition to all the muscles, there are also many ligaments, bursae and nerves that are all coordinating the small space between the trunk and the upper limb.
The lesson is that the shoulder is an entire system, if we want to prevent shoulder injuries we have to address the whole of the moving parts, as focusing only on one aspect will increase stress on the others.

Shoulder Stability

The term “shoulder stability” can cause a little confusion, yet the concept is the most fundamental to most rehabilitation protocols. Shoulder stability refers to the ability of multiple muscles to efficiently combine in movement.



The video above shows “scapulohumeral rhythm” which indicates the scapula has to rotate 60 degrees in order for the 180 degrees of abduction to occur. This involves even recruitment of many different muscles. If any part of this movement is inefficient the entire system will be dysfunctional.

Shoulder Stress

Biomechanics teaches us that the shoulders strongest position is when the arm is tucked in close to the trunk. The further the arm is raised away from the body the more stress is added on the shoulder joint. Add a load in the hands and the pressure on the shoulder is magnified significantly. One acute event that causes the stress at the shoulder to be unbearable will result in injury. There are two ways to prevent shoulder injury in this manner:
1. Correct technique to prevent stress on the shoulder
2. Improving the muscle strength and endurance to increase the threshold before injury.
 

Reducing incidence of shoulder stress

Usually, increased awareness of shoulder mechanics can go a long way to reducing the risk of injury. Learning correct techniques to prevent shoulder injury is an everyday task. There’s no one size fits all approach as all our daily duties are different, but I have listed a few examples to illustrate the idea:

• Keep the arm close to the body where possible. For example,
  • Putting the shopping bags down before opening the front door
  • Squatting down to pick up a child off the ground rather than reaching down
  • Asking staff to grab something off the top shelves at the store rather than reaching
  • Standing close to the pot as you stir
  • Bringing the clothes line down while you hang the clothes then raising it if needed.

• Reducing load on the arms. For example:
  • Pushing a trolley rather than carrying a basket at the supermarket
  • Making multiple trips to carry something rather than overloading

Improving the system

This is where an exercise physiologist can come in. Depending on the tasks you undertake everyday, certain exercises can help train the relevant muscles to stabilise and control the shoulder joint through those movements. Most people benefit greatly from exercise therapy following an injury, but therapy may be even more pivotal to prevent injury in the first place.

Case Study

Recently, a middle aged lady working at the checkout of a supermarket presented with shoulder injury that was preventing her from abducting her arm above shoulder height. She revealed that for 40 hours a week she was passing items from left to right across her body. As she continued to do this, muscles in her left arm are adducting while the right arm is abducting, causing imbalance. Additionally, her shoulder system was stressed too much when she reached across the counter to drag a trolley around where she felt a sharp pain in her shoulder. The supraspinatus muscle had been over-stressed causing it to tear. If she had engaged in exercises to improve her shoulder stability, the injury could have been prevented.

Long Term Risks of Recurring Injury

• Frozen Shoulder – also known as “adhesive capsulitis” involves a build up of scar tissue following repeat injuries that have not been adequately rehabilitated. Eventually, the shoulder cannot rotate past a certain point resulting in a severe limitation of function.
• Chronic Pain – Pain is the brain trying to protect an injured region. Following recurring, untreated injury, many shoulder injury sufferers experience chronic pain as a result of the damage caused by injury.
• Nerve Impingement –  if there is persistent tightening/imbalance of local muscles, stress can be applied on nerves passing through causing numbness and pain through the elbow and hand.
• Comorbidities – Poor, unmanaged shoulder issues can result in neck, back and other upper limb issues that arise following muscle imbalance.
  
  

Conclusion

Shoulder injuries are an inconvenient and uncomfortable injury to suffer. A shoulder injury can disrupt work, activities of daily living and many of life’s most enjoyable adventures. If the requirements of job or family life require frequent and unavoidable use of the arms, take the time to improve the system in order to prevent or reduce the risk of injury. A little foresight goes a long way.