EFFECTIVENESS OF REAR SUSPENSION IN REDUCING SHOCK EXPOSURE TO MANUAL WHEELCHAIR USERS DURING CURB DESCENTS
Andrew M. Kwarciak, BSE; Rory A. Cooper, PhD; Erik J. Wolf, BSE.
The plots show the mean peak-to-peak seat accelerations and the mean frequency weighted peak-to-peak seat accelerations for every wheelchair tested. The accelerations recorded from each chair increase along with each increase in curb height. The Quickie XTR experienced the lowest accelerations for each curb height. Overall, there does not appear to be any significant difference between the performance of the standard and suspension manual wheelchairs.
Slide text:Behavior of the accelerations indicate that the shock reducing elements do not adequately reduce seat vibrations transmitted to the user during curb descents.
This plot shows the average seat acceleration at each of the three curb heights for the folding x-brace wheelchairs, the suspension wheelchairs, for just the Colours Boing and Invacare A6S wheelchairs, and for just the Quickie XTR wheelchairs. These four curves demonstrate a near linear relationship between curb height and measured seat acceleration and the difference in performance between the XTR and the other two suspension models.
The folding x-brace wheelchairs had the highest seat accelerations at both the 4 and 6 curb height, whereas the Boing and A6S group had the highest seat acceleration at the 2 curb height. Conversely, the XTR had the lowest seat acceleration at every curb height. As a result the XTR skewed the combined suspension wheelchair data, lowering the overall averages for the group.
There was no significant difference between the XTR and the x-brace wheelchairs; however, the differences between the two were much greater than those calculated between both wheelchair types.
Slide text:1. Pope MH, Wilder DG, Magnusson ML. A review of studies on seated whole body vibration and low back pain. Proc Instn Mech Engrs 1999; 213(H): 435-446.
2. Griffin MJ, Handbook of Human Vibrations. San Diego: Academic Press Inc., 1990. p 173-186.
3. Dupuis H, Hartung E, Haverkamp M, Acute Effects of Transient Vertical Whole-Body Vibrations. Int Arch Occ Env Health 1991; 63: 261-265.
4. Evaluation of Human Exposure to Whole-Body Vibration Part 1: General Requirements, (1985). ISO 2631-1, Washington, DC: ANSI Press.
This study was partially supported by the National Institute on Disability and Rehabilitation Research, Rehabilitation Engineering Research Center (H133E990001), and the U.S. Department of Veterans Affairs, Rehabilitation Research and Development Service (F2181C).
Updated: May 6, 2003
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Please note: This information is provided a archival information from the Rehabilitation Engineering Research Center on Wheeled Mobility from 1993 to 2002.