Increased Seat Dump Angle in a Manual Wheelchair Is Associated With Changes in Thoracolumbar Lordosis and Scapular Kinematics During Propulsion.
To quantify and compare spinal curvature and shoulder kinematics throughout the manual wheelchair (MWC) propulsion cycle for individuals with spinal cord injury (SCI) who were seated at 2 different seat dump angles.



Single-group, repeated-measures study.



Academic medical center.



Individuals (N=28) with SCI or spinal cord disease who used MWCs completed a telephone screening, and 21 of them were eligible and completed the study.



Participants' personal MWCs were modified to have seat dump angles of 0° or 14°, with a vertical backrest. Participants completed at least 3 propulsion cycles in each condition, during which spine and shoulder motion data were collected with fiberoptic and electromagnetic sensors, respectively.



Thoracolumbar spinal curvature, glenohumeral kinematics, and scapulothoracic kinematics at the start of push (SP), mid-push (MP), end of push (EP), and mid-recovery.



Participants had significantly less lordosis in the 14° condition for all propulsion events. Median differences ranged from 2.0° to 4.6°. Lordosis differences were more pronounced in those with low SCI. Scapulothoracic internal rotation was increased in the 14° condition at SP and MP (mean differences, 2.5° and 2.7°, respectively). Relative downward rotation increased in the 14° condition at SP and MP (mean differences, 2.4° and 2.1°, respectively). Scapulothoracic differences were more pronounced in those with high SCI. No glenohumeral rotations were significantly different between the conditions.



Scapulothoracic kinematics and spinal curvature differences during propulsion may be associated with the position of other body segments or postural stability. Because no differences were observed at the glenohumeral joint, the risk of subacromial impingement may not be affected by this seat angle change.
Mayo Graduate School, Center for Clinical and Translational Science, Mayo Clinic, Rochester, MN.
Beth A
BA
Cloud
Rehabilitation Medicine Research Center, Department of Physical Medicine and Rehabilitation, Mayo Clinic, Rochester, MN. Electronic address: zhao.kristin@mayo.edu.
Kristin D
KD
Zhao
Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN.
Arin M
AM
Ellingson
Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN.
Ahmad
A
Nassr
Department of Neurology, Mayo Clinic, Rochester, MN.
Anthony J
AJ
Windebank
Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN.
Kai-Nan
KN
An
D000328:Adult; D001696:Biomechanical Phenomena / Q000502:physiology; D006233:Persons with Disabilities; D004867:Equipment Design; D005260:Female; D006801:Humans; D008141:Lordosis / Q000503:physiopathology*; D008297:Male; D011187:Posture / Q000502:physiology; D012785:Shoulder Joint / Q000503:physiopathology*; D013118:Spinal Cord Diseases / Q000503:physiopathology*; D013119:Spinal Cord Injuries / Q000503:physiopathology*; D014910:Wheelchairs
Posture; Rehabilitation; Shoulder; Spinal cord injuries; Spine; Wheelchairs