Dynamic Stiffness and Transmissibility of Commercially Available Wheelchair Cushions Using a Laboratory Test MethodBy Garcia-Mendez, Yasmin; Pearlman, Jonathan L.; Cooper, Rory A.; Boninger, Michael L.; Journal of Rehabilitation Research and Development, Volume 49, Number 1, pages 7-22
Publication Date: 2012
Study evaluated and compared the vibration transmissibility of commercially available wheelchair cushions with two laboratory test methods. The study was undertaken as evidence suggests that wheelchair users are exposed to unhealthy levels of vibration when using their chairs, and that the wheelchair cushions may amplify vibrations. The test methods used were (1) direct measurement of transmissibility while 14 study participants without disabilities propelled a wheelchair over a road course with different cushions and (2) characterization of cushions with a material testing system (MTS) combined with mathematical models of the apparent mass of the human body. Seven cushions were selected for testing: Meridian Wave, Invacare Comfort Mate, and Zoombang Protective Gear foam cushions; ROHO HIGH PROFILE, ROHO LOW PROFILE, and Vector with Vicair Technology air-based cushions; and a Jay J2 Deep Contour gel-based cushion. Results showed that although dynamic characterization of wheelchair cushions is possible with an MTS, the results did not correlate well with the transmissibility obtained in the wheelchair road course. Significant differences were found for transmissibility among the cushions tested, with the air-based cushions having lower transmissibility than the foam- or gel-based cushions. Based on study results, it is recommended that air-based models be considered when selecting a cushion to help reduce vibration exposure or as a precaution against spinal pain. Implications for future research focused on developing mathematical models of the body to predict the dynamic response occurring during wheelchair propulsion are discussed.
Assistive Products Discussed: ROHO LOW PROFILE DRY FLOATATION CUSHION
VA Rehabilitation Research & Development Service (Web Site: http://www.rehab.research.va.gov )
Link to text: http://www.rehab.research.va.gov/jour/2012/491/garciamendez491.html