441 JRRD JRRD Volume 47, Number 5, 2010 Pages 441–456 Journal of Rehabilitation Research & Development Evaluation of aluminum ultralight rigid wheelchairs versus other ultralight wheelchairs using ANSI/RESNA standards Hsin-yi Liu, MS; 1 Jonathan Pearlman, PhD; 1 Rosemarie Cooper, MPT; 1–2 Eun-kyoung Hong, MS; 1 Hongwu Wang, MS; 1 Benjamin Salatin, BS; 1 Rory A. Cooper, PhD 1,3–4* 1 Human Engineering Research Laboratories, Department of Veterans Affairs (VA), Rehabilitation Research & Devel- opment Service, VA Pittsburgh Healthcare System, Pittsburgh, PA; and Department of Rehabilitation Sciences and Technology, University of Pittsburgh, Pittsburgh, PA; 2 Center for Assistive Technology, University of Pittsburgh Medi- cal Center, Pittsburgh, PA; 3 Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA; 4 Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA Abstract—Previous studies found that select titanium ultralight rigid wheelchairs (TURWs) had fewer equivalent cycles and less value than select aluminum ultralight folding wheelchairs (AUFWs). The causes of premature failure of TURWs were not clear because the TURWs had different frame material and design than the AUFWs. We tested 12 alu- minum ultralight rigid wheelchairs (AURWs) with similar frame designs and dimensions as the TURWs using the Ameri- can National Standards Institute/Rehabilitation Engineering and Assistive Technology Society of North America and Inter- national Organization for Standardization wheelchair standards and hypothesized that the AURWs would be more durable than the TURWs. Across wheelchair models, no significant differ- ences were found in the test results between the AURWs and TURWs, except in their overall length. Tire pressure, tube-wall thickness, and tube manufacturing were proposed to be the fac- tors affecting wheelchair durability through comparison of the failure modes, frames, and components. The frame material did not directly affect the performance of AURWs and TURWs, but proper wheelchair manufacture and design based on mechanical properties are important. Key wo rds: aluminum wheelchair, ANSI/RESNA, durability, fatigue life, fatigue mode, manual wheelchair, titanium wheel- chair, ultralight wheelchair, wheelchair, wheelchair standards. INTRODUCTION Clinical guidelines recommend ultralight wheel- chairs as the most appropriate wheelchairs for active manual wheelchair users [1]. The reduced weight of ultralight manual wheelchairs helps preserve users’ upper-limb function by reducing the force required to Abbreviations: ANSI = American National Standards Institute, AUFW = aluminum ultralight folding wheelchair, AURW = aluminum ultralight rigid wheelchair, CDT = curb-drop test, CoG = center of gravity, CV = coefficient of variation, DDT = double-drum test, EC = equivalent cycles, FDA = U.S. Food and Drug Administration, HERL = Human Engineering Research Laboratories, ISO = International Organization for Standardization, OEM = original equipment manufacturer, RESNA = Rehabilitation Engineering and Assistive Technol- ogy Society of North America, SD = standard deviation, TURW = titanium ultralight rigid wheelchair, VA = Depart- ment of Veterans Affairs. * Address all corr espondence to R ory A. Coo per, PhD; Human Engineering Research Laboratories (151R-1H), VA Pittsburgh Healthcare System, 7180 Highland Drive, Pitts- burgh, PA 15206; 412-954-5287; fax: 412-954-5340. Email: rcooper@pitt.edu DOI:10.1682/JRRD.2009.08.0137