Investigating Muscle Synergies in Individuals with Spinal Cord Injury: A Scoping Review Protocol

<b>ABSTRACT</b><b>Objective:</b> This scoping review aims to map the methodologies, applications, and outcomes of studies investigating muscle synergy extraction in individuals with spinal cord injury.<b>Introduction:</b> Spinal cord injury impairs central motor control and leads to complex neuromuscular alterations. Muscle synergy analysis, which examines patterns of coordinated muscle activation, has gained attention in neurorehabilitation research for its potential to clarify motor control strategies and compensatory mechanisms. While this approach has been widely applied in populations with stroke, its use in individuals with spinal cord injury remains limited and has not yet been comprehensively reviewed.<b>Inclusion criteria</b><b>:</b><b> </b>Studies involving adults diagnosed with spinal cord injury (complete or incomplete, traumatic or non-traumatic) will be considered. Eligible studies must include the extraction or analysis of muscle synergies using techniques such as non-negative matrix factorisation or comparable algorithms applied to electromyographic data.<b>Methods:</b> The review will follow the Joanna Briggs Institute methodology. A comprehensive search will be conducted across MEDLINE, CINAHL Complete, Scopus, IEEE Xplore, and Web of Science, covering records from database inception to May 2025. Additional sources will include grey literature and reference lists. No limitations will be imposed on study design or publication type; however, only studies published in English will be included. Two reviewers will independently screen titles, abstracts, and full texts. Data extraction forms will be developed and piloted to systematically chart relevant variables. Results will be presented in tables and summarised narratively.<b>Conclusions:</b> This scoping review will comprehensively map the use of muscle synergy extraction in individuals with spinal cord injury. Findings will support researchers and clinicians by clarifying the current state of the evidence and highlighting knowledge gaps in this emerging field.