Workplace shoulder and back injuries are a significant cost for maritime employers. Muscle-related strain injuries are a leading cause of injuries for the maritime industry and generally account for one-third of the workers’ compensation spend. The back and shoulder are two of the main body parts that are frequently injured. To prevent these types of injuries, we need to understand the risk factors and the strategies to minimize or prevent them.
Understanding Shoulder Anatomy
The shoulder is a “ball and socket” joint that is formed by the shoulder blade (scapula), collar bone (clavicle) and arm bone (humerus). The shoulder is very mobile and can move in a wide variety of directions and motions. With this great mobility comes instability. To support the shoulder, there are a wide variety of muscles and ligaments. The primary muscles are the deltoids, which allow the arms to move forward, sideways, and backwards, and the rotator cuff, which is made up of four individual muscles and helps to stabilize the shoulder joint and aid in various shoulder motions. Fluid-filled sacs, called bursa, help to reduce friction and lubricate the joint, allowing tendons to glide freely. Two common shoulder injuries include tendonitis (inflammation of muscle tendons) and bursitis (inflammation of bursa).
Understanding Back Anatomy
The back is a curved column of individual bones, called vertebrae, that provide load bearing support for the spine in four distinct regions: neck (cervical), middle (thoracic), lower (lumbar) and tailbone (sacrum).
Through the vertebrae runs the spinal cord, which transmits information from the brain to your arms and legs. Between the vertebrae are discs that act as “shock absorbers”. Discs are composed of two parts: a tough outer ring and a soft inner “gel” core.
Damage to the disc can cause the “gel” core to pinch a nerve in the spine and cause leg pain. This is known as herniated disc and the resulting leg pain is called sciatica.
There are numerous layers of muscles and ligaments that support and stabilize the spine and supports the foundation of our entire body.
Ergonomic Risk Factors for Shoulder and Back Injuries
As I discussed in a previous Longshore Insider article, there are four main ways the body can become injured: high force from a single event, low force that is frequently repeated, low force that is constant or static, and cumulative loading over time without enough recovery.
The three primary ergonomic risk factors for shoulder and back injuries include:
Strategies to Minimize Shoulder and Back Injuries
The human body works by a series of levers and pulleys controlled by muscles, tendons and bones. Mechanical advantages make some positions stronger than others. For instance, working with your elbows above your shoulders or reaching at an arm’s length reduces your shoulder strength by 40%. Back bending and reaching can reduce your lifting capability by 80% when the reach increases from 10” to 30”.
Here are a few tips to help reduce your risk of injury.
1. Minimize time in the “red zone” by designing and planning your work ahead of time
Review jobs prior to starting to find ways to get in a better and safer position. Use the Go Green graphic (see right, click to enlarge) to help identify positions of higher risk and less strength capabilities. Keep red zone postures to less than 50% of the work day.
Practical solutions to get you in a better position include:
2. Minimize forceful motions
3. Minimize red zone positions and jobs, when possible
Sometimes it may not be feasible to eliminate working in a red zone position. When this happens, consider using some of these techniques:
Remember, prevention is the key; take the time to evaluate your workplace and implement some of the solutions above. Soon, we’ll share an article on strategies to protect aging workers from overexertion injuries.
GoGreen Work in Your PowerZoneTM images and materials are © 2018 ErgoHP LLC. For permission to use them in your facility, please contact Ben Zavitz at email@example.com.
Ben Zavitz, CPE is the President and Chief Ergonomist of Ergo Human Performance LLC, an ergonomics and human performance consulting firm that has developed many unique tools, methods, solutions, and programs for the Maritime Industry that minimizes risks and losses, and maximizes efficiency and company goals. He is a Board Certified Professional Ergonomist (CPE) with more than 20 years of experience implementing ergonomic, safety and process improvement programs for General Dynamics, Boeing, and many Fortune 500 companies. Ben was the lead author of the OSHA Voluntary Ergonomic Guidelines for Shipyards and participated in the National Shipbuilding Research Program (NSRP) projects to develop and test solutions to address ergonomic/injury risk factors. He is a member of the CDC/NIOSH NORA Musculoskeletal Health Cross-Sector Council, Vice President of the Applied Ergonomics Society, and Program Chair for the Applied Ergonomics Conference, and has won several awards for his innovative and unique approach to ergonomics in the Maritime Industry.