Assessing the subjective effects of a passive low-back exosuit in manual urban waste collection: a pilot study

Abstract

This pilot study evaluated the subjective effects of a commercial low-back support exosuit during standard work operations in manual urban waste collection, a sector characterized by high prevalence of work-related musculoskeletal disorders (WMSDs). Although occupational exoskeletons (OEXOs) and exosuits are considered a viable solution to mitigate the risk of developing WMSDs, their actual workplace adoption remains limited. Empirical field data regarding the real-world use of OEXOs, particularly exosuits, is still scarce, necessitating more field studies to investigate real-world complexities. Moreover, while manual waste collection stands out due to its physically demanding nature, with repetitive bending and lifting, awkward postures and high operational pacing, there is little knowledge about OEXOs use in this context. This study addressed both gaps by providing insights into subjective contextual exosuit experience and potential barriers to the integration of wearable assistive technologies into work procedures.Ten waste collectors from an Italian waste management company participated in the study, wearing the Herowear Apex 2, a passive soft low-back exosuit, for approximately two hours during standard work shifts. This device features a backpack-like module, thigh sleeves, a clutch mechanism and elastic bands that store energy during bending and return it during lifting. The device was selected for its quick-engagement clutch mechanism and low-profile architecture. Participants received exosuit training the day prior to the trial and were supervised by researchers throughout the study. A mixed-methods approach was adopted. Quantitative data were collected post-trial using the NASA-TLX scale, the Local Body Discomfort (LBD) scale and an ad hoc five-point Likert-like questionnaire. Qualitative data included post-trial semi-structured interviews. Given the pilot sample size (n=10), descriptive statistical analysis was performed on quantitative data, while thematic analysis was used for qualitative data.NASA-TLX results indicated that the overall perceived workload with and without exosuit was comparable, with slight improvements in physical demand and performance when wearing the device. The LBD scale showed the participants found the exosuit generally comfortable, with light discomfort reported across the body regions. The Likert questionnaire revealed high variability regarding perceived usefulness, while participants broadly agreed on ease of operating the device, social acceptability, preserved range of motion and increased sweating due to the device.Qualitative findings provided critical operational insights. Significant concerns were raised regarding increased thermal discomfort, with unanimous worry about summer usability when sweat could make the device difficult to tolerate. Although there was general agreement on the simplicity of the clutch mechanism, high operational pacing and traffic pressure discouraged continuous manual activation. Participants also noted that the device did not address discomfort in the shoulders and knees, highlighting the regional limitations of a low-back support system in this context. A key functional trade-off was identified: in the passive system, users must exert effort to load the elastic element during trunk flexion to receive assistive force during the subsequent lift, a dynamic that may reduce perceived benefits.These findings contribute field-level evidence on OEXO use and point to contextual factors that must be addressed for successful integration of exosuits in physically demanding occupational settings.

Keywords: Occupational exoskeleton, Exosuit, Manual waste collection, Work-related musculoskeletal disorders, Field study, Usability, User experience

DOI: 10.54941/ahfe1008072