Preliminary Study of an Exoskeleton Index for Ergonomic Assessment in the Workplace

Abstract

Work-related low-back disorders represent the most common and costly musculoskeletal problems, so, recently, industrial exoskeletons have been developed to prevent injury by reducing the load on the back. Their effects are described by a growing body of literature, but is not captured by any standard risk index used in ergonomic practice. This study aims to suggest a method to quantify how the effect of a back-support exoskeleton might be accounted in the NIOSH Lifting Index. Twelve subjects participated in the study and we recorded the surface electromyographic signals of the erector spinae longissimus. Subjects held four different loads in a static position for 10 s without the exoskeleton and wearing it. A substantial reduction in the median of the muscle activity when wearing the exoskeleton was observed. We suggest that this reduction could be reflected in a multiplicative factor that directly affects the NIOSH Lifting Index.