Exoskeleton technology shows promise in protecting workers in one of the most dangerous jobs

The same exoskeleton principles that protect grasshoppers, crabs and similar creatures could also help protect the 25,000 or so workers in the job with the highest injury and fatality rates in America: forestry.

“Forestry is vitally important to our economy and our standard of living, but its workers pay a high price, with an injury rate that is 40 percent higher than the average of all other industries and fatality rates that are 20 to 30 times higher,” said Jeong Ho “Jay” Kim, PhD, a systems engineering expert with the Texas A&M University School of Public Health.

In a recent study, Kim and co-author Woodam Chung, PhD, a forest engineer at Oregon State University, were the first to objectively measure biomechanical stress experienced by professional timber fellers during actual timber felling operations. They also evaluated forest workers’ perceptions of wearable exoskeletons—emerging technology already being used in other physically demanding industries such as shipbuilding and automotive and aerospace manufacturing.

Kim said that most forestry injuries and fatalities are associated with manual timber felling with a chain saw and related activities such as delimbing and cutting felled trees into logs and other smaller pieces. These activities require forceful exertions, awkward postures, repetitive motions and hand-arm vibrations. As a result, more than 70 percent of forestry workers experience work-related musculoskeletal disorders, primarily in their shoulders and lower backs.

These risks are magnified by the isolated, rugged conditions in which this work takes place—often on terrain with unstable footing and unpredictable weather, Kim said.

Kim and Chung’s work was supported by the Economic Development Administration and National Institute for Occupational Safety and Health and published in the International Journal of Forest Engineering.

Study participants were recruited as a convenience sample through local forest industry partners, the Pacific Northwest Agriculture Safety and Health and USDA Forest Service District Offices in Oregon and Idaho.

The study had two parts. First, to identify the types of exoskeletons that would be most appropriate and beneficial, the researchers measured the biomechanical stress levels of 10 currently employed professional timber fellers—nine men and one woman, all age 21 or older—who performed manual timber felling while wearing sensors.

Inertial measurement unit sensors were placed on the participants’ torsos (the midpoint of sternum) and the outside of both arms directly below the shoulder. As the participants worked their shifts of three to four and a half hours, all three sensors continuously synchronized via Bluetooth and saved the data. When the work shifts were completed, the researchers removed the sensors and saved the data into a cloud server.

These participants also completed a paper survey that assessed how much they knew about exoskeletons, how accepting they were of the concept, and their perceived barriers and risks of using exoskeletons. In addition, another 12 currently employed foresters (all male) took the same survey online.

The 22 respondents were primarily in Oregon, followed by Montana, Idaho and Washington, and reported 38 job titles (many of them had multiple roles). They were timber fellers, managers/CEOs, equipment operators, safety officers, cable logging crew members and trainers.

The survey identified musculoskeletal pain in seven different body parts: neck, shoulders, low back, wrist/forearms, knees, legs, and ankles/feet. Low back was the most prevalent, with a pain level of 3.7 on a 10-point scale.

“This finding suggests that back-support and upper-limb support exoskeletons may be suitable to the forestry industry,” Kim said.

In addition, most participants—about 53 percent—were not familiar with assistive technologies such as exoskeletons at all, while 21 percent said they were slightly familiar.

“Upon learning about exoskeletons, these participants had considerable interest in using them for timber felling, cutting/sawing and mechanic work as long as they did not impair mobility and were affordable and easy to use and maintain,” Kim said, adding that weight and the risk of getting snagged were potential concerns.

“While our study sample was too small to be generalizable, the results provided a strong foundation for our current federally funded work to further assess the ways exoskeletons could help forestry workers stay safer on the job,” Kim said.

By Ann Kellett, Texas A&M University School of Public Health

###