  Citation: Candiotti, J.L.; Neti, A.; Sivakanthan, S.; Cooper, R.A. Analysis of Whole-Body Vibration Using Electric Powered Wheelchairs on Surface Transitions. Vibration 2022, 5, 98–109. https://doi.org/10.3390/ vibration5010006 Academic Editors: Setsuo Maeda, Ying Ye, Cyriel Diels and Jelte Bos Received: 30 December 2021 Accepted: 27 January 2022 Published: 30 January 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). vibration Article Analysis of Whole-Body Vibration Using Electric Powered Wheelchairs on Surface Transitions Jorge L. Candiotti 1,2, * , Ahlad Neti 1,2 , Sivashankar Sivakanthan 1,3 and Rory A. Cooper 1,3 1 US Department of Veterans Affairs, Pittsburgh, PA 15206, USA; neti.ahlad@pitt.edu (A.N.); sis65@pitt.edu (S.S.); rcooper@pitt.edu (R.A.C.) 2 Bioengineering Department, School of Engineering, University of Pittsburgh, Pittsburgh, PA 15260, USA 3 School of Health and Rehabilitation Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA * Correspondence: jlc118@pitt.edu; Tel.: +1-(412)-822-3696 Abstract: Wheelchair users are exposed to whole-body vibration (WBV) when driving on sidewalks and in urban environments; however, there is limited literature on WBV exposure to power wheelchair users when driving during daily activities. Further, surface transitions (i.e., curb-ramps) provide wheelchair accessibility from street intersections to sidewalks; but these require a threshold for water drainage. This threshold may induce high WBV (i.e., root-mean-square and vibration-daily-value accelerations) when accessibility guidelines are not met. This study analyzed the WBV effects on power wheelchairs with passive suspension when driving over surfaces with different thresholds. Additionally, this study introduced a novel power wheelchair with active suspension to reduce WBV levels on surface transitions. Three trials were performed with a commercial power wheelchair with passive suspension, a novel power wheelchair with active suspension, and the novel power wheelchair without active suspension driving on surfaces with five different thresholds. Results show no WBV difference among EPWs across all surfaces. However, the vibration-dose-value increased with higher surface thresholds when using the passive suspension while the active suspension remained constant. Overall, the power wheelchair with active suspension offered similar WBV effects as the passive suspension. While significant vibration-dose-value differences were observed between surface thresholds, all EPWs maintained WBV values below the ISO 2631-1 health caution zone. Keywords: accessibility; discomfort; architectural barriers; suspension; wheelchair 1. Introduction There are about 5.5 million wheelchair users in the United States (US) [1]. Wheelchairs provide independent mobility [2], comfort [3], and quality of life for people with disabilities to participate in communities [4]. However, the technology may be limited by surface conditions. For instance, multiple studies have demonstrated that manual wheelchair users are exposed to whole-body vibrations (WBVs) when driving on uneven and rough surfaces for long periods of time [5]. This exposure causes negative effects such as pain in the lower back, neck, and buttocks and increases the rate of muscle fatigue [6–8]. The International Standards Organization (ISO) Standard 2631-1: Mechanical Vibration and Shock. Part 1: Evaluation of Human Exposure to Whole Body Vibration 1 was established to assess the health concerns associated with WBV [9]. The standard defines a health guidance caution zone using the root-mean-square value of the weighted acceleration (RMS, unit: m/s 2 ) and the vibration dose value (VDV, unit: m/s 1.75 ). Based on an eight-hour exposure, a lower limit was defined at 0.5 m/s 2 for RMS and 9.1 m/s 1.75 for VDV. Research has shown that manual wheelchair users are exposed to vibration levels exceeding these standard recommendations [5] and tend to be exposed to vibration for about 13 h per day [6]. Further, the vibration levels may vary depending on different factors including the device suspension and ground surface properties (e.g., roughness [10]). Although ISO 2631-1 (1997) has served as a form of standardized guidance in many studies for WBV exposure Vibration 2022, 5, 98–109. https://doi.org/10.3390/vibration5010006 https://www.mdpi.com/journal/vibration