this article and any supplementary material should be cited as follows: garcia-mendez y, pearlman...

This article and any supplementary material should be cited as follows: Garcia-Mendez Y, Pearlman JL, Cooper RA, Boninger ML. Dynamic stiffness and transmissibility of commercially available wheelchair cushions using laboratory test method. J Rehabil Res Dev. 2012;49(1):XX–XX. http://dx.doi.org/10.1682/JRRD.2011.02.0023

Slideshow ProjectDOI:10.1682/JRRD.2011.02.0023JSP

Dynamic stiffness and transmissibility of commercially available wheelchair cushions

using a laboratory test method

Yasmin Garcia-Mendez, BS; Jonathan L. Pearlman, PhD; Rory A. Cooper, PhD; Michael L. Boninger, MD

This article and any supplementary material should be cited as follows: Garcia-Mendez Y, Pearlman JL, Cooper RA, Boninger ML. Dynamic stiffness and transmissibility of commercially available wheelchair cushions using laboratory test method. J Rehabil Res Dev. 2012;49(1):7–22. http://dx.doi.org/10.1682/JRRD.2011.02.0023


• Study Aim– Evaluate and compare vibration transmissibility of

commercially available wheelchair cushions by:• Directly measuring transmissibility during wheelchair propulsion.• Characterizing cushions with combined material testing and

mathematical modeling of human mass.

• Relevance – Wheelchair users are exposed to vibration.

• This may contribute to high prevalence of back and neck pain.• Characterizing cushion/seating system response to vibrations will help

us better understand whether harmful vibrations are entering body.



Methods

• Selected 7 commercially available cushions. • Measured seated transmissibility for each

seat cushion during field tests: – 14 nondisabled subjects propelled wheelchairs

over road course.

• Estimated maximum seat transmissibility and frequency from material testing system and mathematical models with 1 or 2 degrees-of-freedom.



Results

Maximum transmissibility and corresponding frequency values: Wheelchair road course versus 1- and 2-DOF seating system models.



Results

• Transmissibility significantly differed for cushions tested.– Air-bladder

cushions had lower transmissibility than foam- or gel-based cushions.



Conclusions• Selection of a proper wheelchair cushion is critical to

the user’s health and safety. – Most important variables are:

• Pressure-relieving properties.• Weight.• Thermal properties.• Cleanability.

• We demonstrated that transmissibility is critical because most cushions amplify vibrations. – Air-based cushions outperformed gel- and foam-based

cushions and should be considered to help reduce vibration exposure or prevent spinal pain.

this article and any supplementary material should be cited as follows: garcia-mendez y, pearlman...

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