title: Muscular activity and physical interaction forces during lower limb exoskeleton use.
abstract: Spinal cord injury (SCI) typically manifests with a loss of sensorimotor control of the lower limbs. In order to overcome some of the disadvantages of chronic wheelchair use by such patients, robotic exoskeletons are an emerging technology that has the potential to transform the lives of patients. However, there are a number of points of contact between the robot and the user, which lead to interaction forces. In a recent study, the authors have shown that peak interaction forces are particularly prominent at the anterior aspect of the right leg. This study uses a similar experimental protocol with additional electromyography (EMG) analysis to examine whether such interaction forces are due to the muscular activity of the participant or the movement of the exoskeleton itself. Interestingly, the authors found that peak forces preceded peak EMG activity. This study did not find a significant correlation between EMG activity and force data, which would indicate that the interaction forces can largely be attributed to the movement of the exoskeleton itself. However, we also report significantly higher correlation coefficients in muscle/force pairs located at the anterior aspect of the right leg. In their previous research, the authors have shown peak interaction forces at the same locations, which suggests that muscular activity of the participant makes a more significant contribution to the interaction forces at these locations. The findings of this study are of significance for incomplete SCI patients, for whom EMG activity may provide an important input to an intuitive control schema.
authors.affiliation: Aspire Centre for Rehabilitation Engineering and Assistive Technology , University College London , Royal National Orthopaedic Hospital, Stanmore, HA7 4LP , UK.
authors.forename: Matthew
authors.initials: M
authors.lastname: Wilcox
authors.affiliation: Aspire Centre for Rehabilitation Engineering and Assistive Technology , University College London , Royal National Orthopaedic Hospital, Stanmore, HA7 4LP , UK.
authors.forename: Ashish
authors.initials: A
authors.lastname: Rathore
authors.affiliation: UCL Interaction Centre , University College London , 66-72 Gower Street, London, WC1E 6EA , UK.
authors.forename: Dafne Zuleima
authors.initials: DZ
authors.lastname: Morgado Ramirez
authors.affiliation: Aspire Centre for Rehabilitation Engineering and Assistive Technology , University College London , Royal National Orthopaedic Hospital, Stanmore, HA7 4LP , UK.
authors.forename: Rui C V
authors.initials: RC
authors.lastname: Loureiro
authors.affiliation: Aspire Centre for Rehabilitation Engineering and Assistive Technology , University College London , Royal National Orthopaedic Hospital, Stanmore, HA7 4LP , UK.
authors.forename: Tom
authors.identifier: 0000-0001-9201-7798
authors.initials: T
authors.lastname: Carlson
keywords: EMG; SCI; anterior aspect; artificial limbs; chronic wheelchair use; electromyography; electromyography analysis; injuries; intuitive control schema; lower limb exoskeleton use; lower limbs; muscular activity; peak interaction forces; physical interaction forces; right leg; robotic exoskeletons; sensorimotor control; spinal cord injury; wheelchairs