Innovative Detachable Two-Way Wheelchair Propulsion System: Enhancing Mobility and Exercise for Spinal Cord Injury Users

Background: Prolonged manual wheelchair usage often leads to musculoskeletal disorders in the upper body of individuals with spinal cord injury (SCI) due to repetitive, unidirectional movements. To mitigate these issues, targeted exercise of the back muscles—particularly those involving pulling movements of the arms and shoulders—is recommended. Therefore, this study aimed to develop a detachable, two-way propulsion system for manual wheelchairs, enabling propulsion through both pushing forward and pulling backward on the wheelchair pushrims. Methods: The propulsion system was engineered using a planetary gear train to facilitate dual-direction propulsion. Specifically, the planetary gear reverses the rotational direction, allowing the wheelchair to advance forward even when users pull the pushrims backward. Thus, the wheelchair can move forward through either pushing forward or pulling backward actions. Results: A prototype of the proposed system was fabricated using 3D printing technology and its functionality was verified. The prototype successfully demonstrated the two-way propulsion capability and the operation of the attachment mechanism. Additionally, the pilot test confirmed that an individual with SCI was able to propel a manual wheelchair equipped with the two-way propulsion system using both propulsion methods and switch between the methods independently while maintaining stability and safety throughout the test. Conclusion: The developed detachable two-way propulsion system shows significant promise as both a mobility aid and an exercise device, potentially reducing musculoskeletal complications among individuals with SCI who regularly utilize manual wheelchairs.