Work-related shoulder injuries cost over $28 billion a year. Safe shoulder movement is very dependent on muscle strength and a coordinated movement of a complex structure. With each passing decade a worker can potentially lose 10% of their muscle strength.  As the work force ages the frequency and costs for shoulder injuries will increase. It is a perfect storm in the making.

How is the shoulder put together and what makes it so vulnerable?  It is made up of three bones, three joints, and a complex dance between multiple muscles, ligaments, and tendons. Let’s break it down into the basics. The bones are the shoulder blade (scapula), the collar bone (clavicle) and the upper arm bone (humerus). The humerus connects to the scapula at the glenoid and is held in position by ligaments and the rotator cuff. The cuff is actually a group of four muscles. The collar bone connects to the scapula and then connects the shoulder to the main skeleton.  That’s right- the only connection for the shoulder to the core is through a little bone called the clavicle. Posture, muscle strength, and movement give the shoulder the rest of its integrity.

How do we injure our shoulder? It can be overloaded during lifting, leaned on causing compression, and damaged trying to dampen the impact of a slip and fall to name just a few work-related causes we often see. How do we reduce the exposure to shoulder injuries?

• Strategy ONE- keep the work below shoulder level. Look at shelves, staging, and storage in your work environment. How much stuff do you store above shoulder level and expect workers to retrieve on a regular basis? Reconfigure the shelving to keep the most frequently accessed items below shoulder level. Some work must be done above shoulder level; HVAC installation comes to mind. Stage fabrication and tool areas ergonomically so a worker can cut and prepare vents and valves at good working heights. Allow for recovery time when possible and include occasional micro stretch breaks.
• Strategy TWO- keep as much work as possible in the “power zone.”Very simply, keep the load to less than 35 pounds and between a worker’s knees and shoulders. Nothing overhead and nothing on the ground. Bend the knees and prepare the core for a lift. This is not only good for the back it is great for the shoulders. Bending the knees engages the core which stabilizes the shoulders and starts that complex dance of lifting. Think like a backhoe- stabilize first then start operating the arm.
• Strategy THREE- pull the load close to the body. For a box on a shelf, bend the knees, engage the core, stagger the hands, slide the box to the hinge point, and draw into the body. Reverse the process putting a box on a shelf. Anything between 36 and 50 pounds get a buddy to help lift. Anything above 50 pounds it’s time to invest in a lift assist device.

Avoid extended reaches to complete a task like bed making. Believe it or not an extended reach by a housekeeper, like making a bed, is an above the shoulder activity and a heavy strain to the back.  Work from both sides of the bed or have a partner. Stay upright and work in the power zone.

Finally, in the office environment keep the head upright and the keyboard and mouse just below elbow height. Anything higher will load the shoulders.  Awkward reaching to an input device like the mouse often leads to leaning on the opposite elbow.  That creates compression and eventually an injury. Subtle changes can have a big impact.  When working at a computer your upper arm should be parallel to your core and forearm parallel to the floor.

Looking for more information on this topic? On September 16, 2021, MEMIC presented a free webinar titled, “Put a Good Head on your Shoulders: To Protect Them from Injury”.  This webinar explored the shoulder anatomy, its exposure to injury in the workplace, the effect of aging, and strategies for recovery and health.

Posted ByAllan Brown, (Retired April 2022)