Volume 44 Number 3 2007
Pages 449 — 458

Abstract - Multisite comparison of wheelchair propulsion kinetics in persons with paraplegia

Alicia M. Koontz, PhD, RET;1-2* Yusheng Yang, PhD;1 Robert Price, MSME;3 Michelle L. Tolerico, MS;1,4
Carmen P. DiGiovine, PhD, RET;5 Sue Ann Sisto, PhD;6-7 Rory A. Cooper, PhD;1-2 Michael L. Boninger, MD;1-2,4

1Human Engineering Research Laboratories, Department of Veterans Affairs Pittsburgh Healthcare System, Pittsburgh, PA; 2Departments of Rehabilitation Science and Technology and Bioengineering, University of Pittsburgh, Pittsburgh, PA; 3Department of Rehabilitation Medicine, University of Washington, Seattle, WA; 4Department of Physical Medicine and Rehabilitation, University of Pittsburgh Medical Center Health System, Pittsburgh, PA; 5Assistive Technology Unit, Department of Disability and Human Development, University of Illinois at Chicago, Chicago, IL; 6Department of Physical Medicine and Rehabilitation, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark, NJ; 7Kessler Medical Rehabilitation Research and Education Corporation, West Orange, NJ

Abstract — A multisite collaborative study is being conducted on the association between propulsion biomechanics and upper-limb injuries. This substudy compared subject characteristics and pushrim kinetics across three sites and identified early on in the main study any differences that could affect interpretation of the findings or data pooling. A total of 42 manual wheelchair users with paraplegia (14 from each site) performed 0.9 m/s and 1.8 m/s steady state propulsion trials and an acceleration-brake-coastdown trial on a wheelchair dynamometer while propulsion forces and moment about the hub were measured with a SmartWheel. Significant differences between two sites were found in peak and average resultant force (p < 0.05), peak and average moment at the slower steady state speed (p < 0.005), and peak and average torque at the faster steady state speed (p = 0.06). Subjects at the site with significantly lower forces and torques had a slower deceleration rate during coastdown compared with the subjects at the other two sites (p < 0.001). These results imply that rolling resistance is lower at one of the sites and likely due to differences in dynamometer properties. A mechanical method was used to site-normalize the data and enable data pooling for future analyses.

Key words: biomechanics, friction, inertia, kinetics, manual wheelchair, paraplegia, propulsion, rehabilitation, rolling resistance, spinal cord injury, wheelchair dynamometer.

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