Wearable exoskeleton devices can reduce some of the mechanical stress of manual labor. These wearable machines can be powered by electricity or by human motion, and they can be as large as a space suit or as small as a glove (approx. $6,000 and weighs about nine pounds.). They are used to amplify or transform worker movements, improve biomechanics and efficiency, and are increasingly prevalent in the public and private sectors. As these devices are deployed more widely in the workplace, sound research is required to assess potential dangers and benefits of this new technology.
Construction is a physically demanding, labor-intensive industry with heavy manual material handling and awkward work postures. Musculoskeletal disorders are a leading cause of injury among construction workers, with overexertion in lifting causing over one-third of these injuries. The rate of work-related musculoskeletal disorders in construction is 16% higher than in all industries combined. Since back injuries are the most prevalent work-related musculoskeletal disorders in construction, and shoulder and other joint injuries are also major causes of injury, exoskeletons present an attractive possibility.
In a study of forward bend lifting using an exoskeleton designed to decrease load to the spine and improve posture, researchers found that exoskeletons decrease total work, fatigue and load while improving posture. This is supported by additional studies. In addition to decreasing load on the spine, exoskeletons have been shown to decrease shoulder discomfort while increasing productivity and work quality among painters and welders.
There are relatively few studies concerning use of exoskeletons in construction to reduce risk factors of load handling. Some field trials have been conducted in Europe. Preliminary results of a recent study in France suggest that a device designed to provide overhead load assistance to the user had the adverse effect of creating additional effort to counteract resistance when the arms moved beyond the intended range. Another French study found that exoskeleton users were able to operate an overhead tool using less force and that users reported “certain types of pain disappeared.” However, this seemed to be a highly specialized task, involving skilled and technical application of plaster, and it is not clear how broadly the preliminary study can be interpreted. Both reports highlighted the importance of considering how the exoskeleton is adapted to the specific work task and the acquired skills of the user.
Much of the research and progress in the U.S. that is relevant to exoskeleton usage in industry and rehabilitation has been supported by the U.S. Department of Defense. The U.S. military, collaborating with the National Center for Manufacturing Sciences, evaluated exoskeleton use in naval shipyard industrial settings. Naval shipyard workers lift heavy hand-held tools and supplies, work in awkward postures, and work at various heights as in construction. A study of the industrial human augmentation system (iHAS), an integrated system composed of two different exoskeletons found that use of the iHAS was associated with an approximately ten percent increase in productivity, a reduction in vibration of the hands, and improved quality of work.
Exoskeletons have the potential to enhance worker productivity, provide assistance to aging workers, and decrease the risk of musculoskeletal disorders. The U.S. National Institute for Standards and Technology (NIST) has examined the need for standards and test methods related to the use of exoskeletons. In Europe, a 2015 European Union (EU) research and development project set out to develop “standards for the safety of exoskeletons used by industrial workers performing manual handling activities.” The effort involved creating an exoskeleton hazard database to describe potential hazards throughout the exoskeleton’s lifecycle; identifying strategies to mitigate and reduce risks; and creating systems to test exoskeleton design concepts for their ability to perform tasks safely. The intent of this effort is to develop policies and standards for exoskeleton use in industry. Currently, there is insufficient data to determine complete safety profiles or health effects for long-term use of exoskeletons. Future research, is needed to develop appropriate standards before construction workers are exposed to the potential hazards associated with their use.