USING THE ABSORBED POWER METHOD TO EVALUATE EFFECTIVENES OF SELECTED SEAT CUSHIONS DURING MANUAL WHEELCHAIR PROPULSION

摘要

Although wheelchair users are constantly subjected to oscillatory and shock vibrations not much research has been conducted to assess the whole-body vibrations experienced by wheelchair users. Studies that have been published have only involved the testing of manual wheelchairs not interventions such as suspension or seating systems.The purpose of this study was to determine if selected wheelchair cushions reduce the amount of harmful whole-body vibrations transferred to wheelchair users and, if the absorbed power method a good measure of evaluating the whole-body vibrations.Thirty-two participants, who use a wheelchair as their primary mode of mobility, partook in this study. Four of the most commonly prescribed wheelchair cushions were selected. Participants were asked to propel their wheelchair over a simulated activities of daily living (ADL) obstacle course while acceleration and force data was collected.A repeated measures ANOVA showed no significant differences between the different cushions for the total averaged absorbed power (p = .190), the 50 mm curb drop (p = .234), or the rumble strip (p = .143). A repeated measures ANOVA for the peak curb drop absorbed power revealed a significant difference in the cushions (p = .043).The cushions that appeared to perform the best in this testing appear to be the Invacare Pindot and the Varilite Solo. Not only did those cushions appear to have the lowest values much of the time but did not display the highest values. Absorbed power appears to be just as effective at determining the effects of vibrations in the time domain as the prescribed methods of the ISO 2631 standard.