The Effects of Upper-Body Exoskeletons on Human Metabolic Cost and Thermal Response during Work Tasks—A Systematic Review

Abstract

Background: New wearable assistive devices (exoskeletons) have been developed for assisting people during work activity or rehabilitation. Although exoskeletons have been introduced into different occupational fields in an attempt to reduce the risk of work-related musculoskeletal disorders, the effectiveness of their use in workplaces still needs to be investigated. This systematic review focused on the effects of upper-body exoskeletons (UBEs) on human metabolic cost and thermophysiological response during upper-body work tasks. Methods: articles published until 22 September 2020 were selected from Scopus, Web of Science, and PubMed for eligibility and the potential risk of bias was assessed. Results: Nine articles resulted in being eligible for the metabolic aspects, and none for the thermal analysis. All the studies were based on comparisons between conditions with and without exoskeletons and considered a total of 94 participants (mainly males) performing tasks involving the trunk or overhead work, 7 back-support exoskeletons, and 1 upper-limb support exoskeleton. Eight studies found a significant reduction in the mean values of the metabolic or cardiorespiratory parameters considered and one found no differences. Conclusions: The reduction found represents a preliminary finding that needs to be confirmed in a wider range of conditions, especially in workplaces, where work tasks show different characteristics and durations compared to those simulated in the laboratory. Future developments should investigate the dependence of metabolic cost on specific UBE design approaches during tasks involving the trunk and the possible statistical correlation between the metabolic cost and the surface ElectroMyoGraphy (sEMG) parameters. Finally, it could be interesting to investigate the effect of exoskeletons on the human thermophysiological response.

Wearables for Biomechanical Performance Optimization and Risk Assessment in Industrial and Sports Applications

“…Results indicated that an exoskeleton significantly reduced the required mechanical energy for tasks, which can help improve worker performance by reducing fatigue [ 6 ]. Based on a series of exoskeleton-based studies, researchers have demonstrated that this assistive-based technology improves both range of motion [ 16 , 17 ] and muscle fatigue or activation [ 16 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 ].…”

Method and Test Course for the Evaluation of Industrial Exoskeletons

“…Additionally, scientific reviews provide informative overviews of applied evaluations of either exoskeletal prototypes or commercial systems. For instance, they focus on the user's metabolic costs with upper-body exoskeletons [21] or muscular activity, body loading, and experience with trunk exoskeletons [22,23]. In contrast, Hoffmann et al [11] present a generic prevalence matrix of different applied types of analysis combined with their respective research objects for deriving patterns and best practices for prospective evaluation methodologies.…”

A physiological and biomechanical investigation of three passive upper-extremity exoskeletons during simulated overhead work

“…Instead of using EMG to measure the effects of upperextremity exoskeletons in the shoulders, physiological measures related to oxidative metabolism could provide a more appropriate picture of the potential of industrial exoskeletons to reduce occupational injury. A multitude of studies have explored the metabolic effects of both low back and upper-extremity exoskeletons, and a recent systematic review reports that the majority of these studies recorded significant reductions in the mean values of metabolic or cardiorespiratory parameters considered (Del Ferraro et al 2020). However, these studies measured global changes rather than localised metabolic changes occurring in the individual muscles of target body areas.…”