Canadian Occupational Safety

20 www.cos-mag.com Canadian Occupational Safety M usculoskeletal disor- ders (MSDs) are among the most common and painful of occupational injuries. Most employers can reduce the risk of these injuries by reorganiz- ing the workspace based on ergonomic principles. However, for many people, the particular environment they work in, or task they perform, make the use of such controls almost impossible. A new and innovative technology may be just the solution. The exoskel- eton, a rigid structure worn on the outside of the body, has been proven to reduce the physical stresses that cause MSDs. As a new technology, exoskeletons are the subject of many studies and tests conducted in occu- pational settings. Their capabilities and potential disadvantages are still being worked out. Safety managers have many factors to consider before knowing whether this new technology will be effective in reducing musculo- skeletal disorders in the workplace. Exoskeletons may prove useful in almost any workplace since the need for the device depends mostly on the task being performed, says Cath- erine Trask, Canada research chair in ergonomics and musculoskeletal health and associate professor at the University of Saskatchewan in Sas- katoon. These tasks are common in construction, which require a lot of heavy manual material handling and awkward postures. Manufacturing, too, involves many tasks that entail common ergonomic risk factors: awkward postures, repeti- tive work, different forces and exposure to vibration. Other industries that may see exoskeletons as a way to decrease MSDs include logistics, shipping, elec- tronics and agriculture. Additionally, the devices may help older workers continue working. There is also research being done into whether they could be useful for people returning to work after an injury, Trask says. "Could they be used in the same way other types of braces might be worn while someone is retraining into their job and their body is recovering? That is still an open question." Beyond industrial use, one major application for exoskeletons is in the military, where they are intended to increase soldiers' strength, endurance and speed. In health care, they assist in the rehabilitation of people with spinal cord injuries. Exoskeletons are classified as "active" or "passive." Active, or pow- ered devices, operate by means of electric motors or batteries. With passive devices, human movement propels the device, which works through materials, springs or dampers. Industrial exoskeletons include whole-body, upper-body and lower- limb devices. Upper-body devices, which look like a complex backpack, are designed to support the arms to reduce muscle and joint fatigue. They decrease risk of shoulder injuries, common among workers doing over- head work. When the worker raises their arms, the device engages, cre- ating a sensation that something is pushing up the elbows. Those worn on the lower body support the knee or the back. "As you bend forward, rather than your back muscles and the discs and ligaments in your back needing to sup- port you, this structure helps pass the load onto your legs. So, if you're bend- ing forward to pick something up, the exoskeleton would make both the bending over and the coming back up a little easier on your back," Trask says. CASE STUDIES Ford Motor Company started develop- ing and testing exoskeletons several years ago, in partnership with vendors and the United Auto Workers union, to try to reduce injuries in the shoul- der and lower back, says Marty Smets, technical expert in human systems and advanced manufacturing at Oakville, Ont.-based Ford Motor Company. "Shoulders are unique joints. They are very fatigable joints. The accumulation of fatigue can lead to musculoskeletal injuries," he says. "Workers with shoulder injuries usu- ally have to be away from work two to three times longer than those with back injuries." In 2018, Ford conducted trials of spring-powered devices in about 20 facilities worldwide, monitoring the feedback from operators. "Putting a small number of devices in different regions helps me under- stand how we can manage these devices globally," Smets says. "Over the next couple of years, as the devices get lighter, cooler, easier to use and more comfortable, we will ramp up our uptake." A year ago, the company launched a two-year study at its Oakville assembly plant that will monitor the use of arm- support exoskeletons among workers doing overhead work. There will also be a control group. The purpose of the study is to gather long-term data on the use of exoskeletons in the workplace. "What we know from the lab studies we've conducted is that the risk factors are being reduced. The amount of activation in the muscle fibres of the shoulder declines by 10 to 40 per cent. Less muscle activa- tion means you're working at a lower percentage of your maximum capa- bility, and that correlates with a lower injury risk," Smets says. At the six-month point, Smets says, they found statistically significant decreases in self-reported discomfort across the upper back, in the wrist and in the neck, as well as trends of decreasing discomfort in the shoulder. "Those who are using exoskeletons have significantly less dis- comfort in those body regions than those performing the same work without an exoskeleton." In another year, Smets adds, they hope to find not only significant declines in subjective discomfort, but also fewer injuries among the workers doing overhead work. In Saskatchewan, Trask has recently launched a research project looking into the utility of exoskeletons among agricultural workers. While farmers perform more varied work than work- ers on a factory assembly line, they are required to do a lot of ground-level work. As an industry, farming has high rates of back pain, especially low back Exoskeletons are reducing ergonomic injuries, but their practicality is being put to the test By Linda Johnson

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