A new method to quantify demand on the upper extremity during manual wheelchair propulsion.
OBJECTIVE
To use an ergonomics-based rating that characterizes both demand on, and capacity of, upper-extremity muscle groups during wheelchair propulsion to help identify the muscle groups most at risk for pain or overuse injury in a relatively demanding wheelchair propulsion task.


METHODS
Case series.


METHODS
Biomechanics research laboratory.


METHODS
Sixteen manual wheelchair users with complete (American Spinal Injury Association grade A) T6-L2 paraplegia.


METHODS
Not applicable.


METHODS
Internal peak joint moments required by each of the major upper-extremity muscle groups for propelling a wheelchair up a ramp; isometric strength of each of the muscle groups in positions simulating wheelchair propulsion; and wheelchair propulsion strength rating (WPSR) for each muscle group, calculated by normalizing the joint demands to their capacity.


RESULTS
The largest joint moment was for shoulder flexion, at 39.7+/-13.9Nm. Shoulder flexion also accounted for the peak WPSR value of 66.5%+/-20.3%. Supination and pronation movements had low peak moment requirements (3.4Nm, 5.0Nm, respectively) but high WPSR values (41%, 53%, respectively).


CONCLUSIONS
Even a relatively benign ramp (2.9 degrees ) places a large demand on the musculature of the upper extremity, as assessed by using the WPSR to indicate muscular demand.
Sabick
Michelle B
MB
Orthopedic Biomechanics Laboratory, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. MSabick@boisestate.edu
Kotajarvi
Brian R
BR
An
Kai-Nan
KN
D000328:Adult; D001165:Arteriovenous Malformations / Q000503:physiopathology; D001696:Biomechanical Phenomena; D006233:Persons with Disabilities / Q000534:rehabilitation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000503:physiopathology / Q000534:rehabilitation; D010264:Paraplegia / Q000503:physiopathology* / Q000534:rehabilitation*; D012785:Shoulder Joint / Q000503:physiopathology*; D013119:Spinal Cord Injuries / Q000503:physiopathology / Q000534:rehabilitation; D013647:Task Performance and Analysis; D014910:Wheelchairs; D014955:Wrist Joint / Q000503:physiopathology