Page 42 - Occupational Health & Safety, October 2018

ERGONOMICS
I n d u s t r i a l E x To s k e l e t o n s : W h a t Y o u ’ r e N o t H e a r i n g
he commercial market for technologies that positive message and a common set of stated benefits: augment human performance in the indus- ■ Reduction in occupational MSDs
trial workplace are ever-expanding. A wide ■ Increased productivity
range of whole-body, lower-limb, and upper- Better quality of work extremity devices now exist. The interest in industrial ■ Increased worker stamina
exoskeletons to improve human performance and to reduce musculoskeletal disorders (MSDs) is extreme- ly high. Vendors and media tout the benefits of these devices, and safety professionals are eager to listen. But what do experts really know about industrial exo- skeletons? And what are you not hearing?
What Are the Basics of Industrial Exoskeletons? Let’s start with the essentials.
■ The definition: The Merriam-Webster dic- tionary defines an exoskeleton as “a wearable, exter- nal mechanical supporting structure.” It is a device that augments human performance by increasing strength, endurance, and other physical capabilities of healthy or able-bodied individuals (Young and Ferris, 2017). For example, it can be used to help a person lift and carry heavy objects and support the weight of heavy tools.
■ The types: These devices are classified as ei- ther active or passive. An active assistive device is powered through actuators, such as electric motors, pneumatics, levers, hydraulics, or a combination of technologies. Passive assistive devices do not in- clude actuators; natural human movement creates the energy that powers the device through materials, springs, or dampers.
■ The supported body parts: The device can be whole-body or joint-specific (for example, lower body, back, upper extremity). It can be hard or soft. Hard devices (exoskeletons) have a rigid human-de- vice interface, which includes a solid frame and rigid structures. Conversely, soft devices (exosuits) have a lighter-weight, soft human-device interface, which in- cludes flexible textiles.
■ Standards: There is currently no established gold standard for assessing these devices for hu- man performance augmentation (Young and Fer- ris, 2017). However, in 2017, ASTM International formed the ASTM Committee F48 on Exoskeletons and Exosuits to develop voluntary consensus stan- dards for exoskeletons, including safety, quality, per- formance, ergonomics, and terminology for systems and components.
What Are Vendors and the Media Saying?
Until recently, the narrative around industrial exoskel- etons has been controlled by vendors and the media. Most of what safety professionals know comes from these sources. Most vendors proclaim a consistent,
■
■ Healthier workforce
These benefits seem very clear and concise. Un- fortunately, this message is not aligned with what researchers are finding. Research shows that benefits are mixed and there several significant physiological consequences of use.
What is Research Finding About
Low-Back Industrial Exoskeletons?
To my surprise, there is very little peer-reviewed, sci- entific research on the benefits and consequences of industrial exoskeletons. At present, there are fewer than 100 papers published. Most evaluate the impact of devices designed to support the lower back or mul- tiple joints during stooped working postures, dynam- ic lifting, static holding of a load, and general support. Unfortunately, most studies involved only one to three participants. In general, these studies measured mus- cle activity (effort), muscle fatigue, and spinal loading. The positive results include the following:
■ Passive devices that assist with dynamic lifting reduce muscle activity by 10 to 40 percent, reduce spinal loading by 23 to 29 percent, and reduce overall muscle fatigue (de Looze et al., 2015).
■ Passive devices that assist with static trunk bending reduce muscle activity by 10 to 25 percent and spinal loading by 12 to 13 percent (de Looze et al., 2015).
However, these devices yielded some unexpected physiological consequences:
■ Increased muscle activity of other joints, specifically the legs
■ Increased energy expenditure (metabolic cost) ■ Reduced range of motion
■ Impeded motion
■ Increased discomfort due to localized contact
pressure
■ Reduced task performance
Based on the research, the results are mixed at best.
What is Research Finding About Upper- Extremity Industrial Exoskeletons?
Over the last few years, there has been a lot of focus on smaller, single-joint devices that support the up- per extremities during sustained overhead work and/ or supporting heavy industrial tools in construction, petrochemical, and large-product manufacturing envi- ronments. A common goal of these devices is to reduce MSDs related to the shoulder during overhead work.
So, what do we know about the passive, upper-
38 Occupational Health & Safety | OCTOBER 2018
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