Page 2 of 4
Ergonomics in Industrial Environments: Hand Protection is the New Frontier
It is a common misperception that Henry Ford invented the first assembly line. That was Ransom Olds, who used the new approach to increase Oldsmobile output by 500 percent in a single year. Ford took note and improved the system to the point that his company became the first to mass-produce the automobile.
However, the concept of the assembly line dates to much earlier. Twelfth century shipbuilders assembled their crafts through a process that bore a striking resemblance to an assembly line. They moved the ships down a canal to different stations where workers performed specific jobs or affixed certain parts. Ask these workers how to build a ship, and they likely shrugged. Ask one how to attach a mast, and he could have been an expert. Eight hundred years later, today's automotive and electronics manufacturing workers certainly can relate.
These concepts—worker specialization and mastery of repeatable tasks—have changed the face of manufacturing and made mass production of countless products possible. They are, by any measure, a gift to society. However, that does not mean their proliferation occurred without consequences to the workers who make it possible.
Repetitive Motion: Mass Production Work-Related Injuries
The assembly line simplified worker responsibilities and created tremendous job opportunities, but it also introduced repetitive motion injuries into the modern workforce in massive numbers. These injuries manifest as musculoskeletal disorders (MSDs) and, according to OSHA, work-related MSDs are among the most frequently reported causes of lost or restricted work time. In fact, the Bureau of Labor Statistics (BLS) reported1 in 2015 that MSD cases accounted for 31 percent of all worker injury and illness cases.
The most common repetitive motion injury, carpal tunnel syndrome, affects more than 8 million people in the United States alone. On average, about 120,000 people annually undergo surgery to relieve work-related carpal tunnel symptoms. This is a significant expense for employers. Workers who suffer repetitive motion injuries, on average, require 23 days to fully recover—14 more than the average for all other injuries. Those injuries cost employers some $80 billion per year.2
Unsurprisingly, employers have taken steps to help reduce the number of repetitive motion injuries in their workplaces. The pursuit of healthier work environments spawned a new area of study—ergonomics—and an industry of its own focused on the development of ergonomic products for a variety of tasks. Office equipment was the first frontier, with desks, desk chairs, and keyboards among the first wave, but some manufacturing equipment adapted to ergonomic principles, as well. Still, repetitive tasks in manufacturing plants are unavoidable.
Ergonomics and Hand Protection
Assembly line workers may tighten the same screw or attach the same clip hundreds of times in a given hour, thousands of times a day, millions of times a year. That sort of repetitive movement, day after month after year, can take a toll, and the hands and wrists often bear the brunt of such repeated exertion. These are complex parts of the body, with 24 bones, 120 ligaments, 48 nerves, and 14 muscles between the forearm and fingertips. These systems work together to perform tasks that require some 25 percent of the motor cortex of the brain to complete. The hands and wrists are as intricately designed as any fine timepiece, and just as susceptible to dysfunction if any single part is out of step. Working in tight spaces or at awkward angles, manipulating heavy objects, and repetitive motion all can cause the type of dysfunction that leads to MSDs.
Today, most manufacturing workers wear gloves to protect their hands while doing their jobs. Those gloves impact the musculoskeletal systems in and around the hands in subtle and not-so-subtle ways, increasing or decreasing the amount of muscle exertion required to perform the necessary tasks. Glove design can work against a given movement, but the same glove may be well suited to a different motion. As always, glove selection is critical.
The impact different glove designs have on muscle exertion may not seem noticeable during a specific task. However, one must remember that workers are performing these tasks hundreds or thousands of times a day. These small differences can have a massive impact over time. Gloves that reduce muscle effort can make the job easier, keep the worker fresh longer, and increase productivity. This is the core tenet of ergonomics. Think of a change jar you might keep on the kitchen counter. A few pennies dropped in the jar at the end of the day won't buy much, but those pennies add up. By the end of the year, the contents of that jar can pay for the kids' Christmas presents or the family vacation.
Of course, small differences can work the other way, as well. If a glove increases hand fatigue, it can cause chronic, degenerative conditions such as tendinitis and arthritis. It can lead to dropped objects, wasted inventory, and increased time off for workers. Perhaps most problematic, it can lead workers to remove their gloves and put their hands at greater risk for severe injuries from cuts, chemical exposure, or crushing.
Testing and Certification
Many gloves are made with a worker's hand in mind, with breathable fabrics or a second-skin design to provide as much comfort as possible. But how can safety managers or workers be confident a glove is going above and beyond to aid hand movement and reduce the impact of repetitive motion, instead of simply being comfortable?
US Ergonomics is a consulting and testing organization that advises on ergonomics around the world and tests and certifies products that meet ergonomic standards for improving user comfort, fit, and productivity while reducing risk factors related to musculoskeletal conditions. They use a set of tests aligned with industry standards to test gloves for ergonomic performance. The tests have two components:
(1) Laboratory testing, including electromyography to measure muscle engagement and the amount of energy used by the muscles to create motion. Other lab tests look at articulation of the hands and fingers, adding resistance to those motions and measuring to ensure the gloves are not restricting movement.
(2) Engagement, with 20-40 users wearing the gloves over a 30-day trial. Those users are surveyed regularly to measure their perception of the glove’s impact on their performance and level of fatigue.
If the gloves pass the laboratory tests and receive at least 70 percent positive feedback during the engagement exercise, they receive ergonomic certification from US Ergonomics. To date, only one line of industrial gloves on the market has received such a certification.
What does ergonomic certification mean? Gloves carrying that certification have shown in testing that they do not add any negative impact to the worker. Neither testing nor certification is required at this time, and many manufacturers choose not to submit gloves for testing. With that in mind, when choosing a glove, be sure to ask about internal testing procedures and ergonomic performance of the glove. Remember, small impacts make a big difference over time.
Bottom line: Ergonomics isn't just about desk chairs any more. There are hand protection solutions available that deliver the comfort, performance, and protection workers need while minimizing hand fatigue and the risk for repetitive motion reactions and MSDs.
This article originally appeared in the November 2018 issue of Occupational Health & Safety.