The effect of out-of-round wheels versus true round wheels on energy costs of pushing a wheelchair

Introduction: It has been assumed that true round wheels are to be preferred compared to out-of-round or untrue wheels. Bicycle and car wheels are balanced and “trued” to ensure a smooth ride and railway wheels that are out-of-round are known to damage the track and railcars. However, there has been very little research on the impact of out-of-round wheels on the mobility or energy cost of wheelchair users. Inexpensive out-of-round bicycle wheels are utilized on some wheelchairs designed for low-resource settings; any impact on mobility would affect those riding in and those assisting by pushing the wheelchair. We hypothesize a study with able bodied wheelchair pushers could give some indication of the impact of out-of-round wheels on assistant pushers. Procedures: Participants (25, 11M, 14F, mean age 22.6, SD+/- 2.37) were able-bodied university students. Protocol was approved by the IRB and class participants gave verbal consent and were free to withdraw at any time. Two identical wheelchairs intended for use in less-resourced settings were obtained. The out-of-round wheels on one were replaced with true bicycle wheels. A repeated measures study design was used with participants pushing each wheelchair occupied by a 75 kg test dummy for a six minute timed walk test (TWT). Heart rate and ml O2/min (VO2) were measured for the last 4 minutes of each test and participants completed two visual analogue scale (VAS) questions after each test rating the ease/difficulty and awkwardness. Order of wheelchair condition was randomized and participants rested between trials. Results: 15 of the 25 participants completed the VAS questionnaire. Comparison of the means indicated that the qualitative results for the VAS question regarding awkwardness differed with out-of-round wheels being rated as more awkward. Comments indicated more wobble and more noise. Conclusion: It would seem that out-of-round wheels are awkward. However, for the degree of out-of-roundness in the wheelchair wheels utilized in this study, energy cost was not affected

A Comparative Study of Two Pediatric Wheelchairs Based on Therapists\u27 Feedback

Summary Receiving feedback from therapists and seating specialists is an important part of evaluating and providing quantitative data to wheelchair manufacturers servicing less-resourced settings. Introduction There is currently a pressing need for research to enable proper donations of wheelchairs to less resourced settings1. To appropriately serve a population of persons with disabilities in a given location, it is important to understand the specific needs of that population2. People living in less resourced settings have a different lifestyle than those residing in more developed countries, and different functionality and design of wheelchairs is needed3. The goal of our study is to compare two pediatric wheelchairs designed for less-resourced settings using questionnaire feedback from clinicians and seating specialists. Methods After working with each wheelchair a least one hour and being involved with fitting a child to that chair, seating specialists, technicians and therapists will complete a visual analogue scale questionnaire with questions on the following: design and manufacturing of 11 structural regions of the wheelchair and 7 additional questions on the likelihood of the wheelchair’s performance in various categories. Preliminary Results Preliminary data indicate the design and manufacturing of the Hope Haven wheelchair is rated higher than the APDK chair in eight regions of the chair and one performance aspect. Conclusion Our sample group of subjects is very small at this point. Additional data collection is planned in conjunction with a trip to Kenya to complete a long term field study of the two chairs. A parallel study with feedback on energy cost of rolling and Follow-up on wheelchair donations and their functionality is an essential part of helping persons with disabilities in less-resourced settings as well as manufacturers

Using Curb and Figure-Eight Skills Tests to Compare Maneuverability of the user assistant team in the Motivation Rough Terrain Wheelchair and the Whirlwind RoughRider Wheelchair

ABSTRACT Some wheelchair users who cannot self-propel use powered chairs. In less-resourced settings powered chairs may not be available and users may rely on assistants to push them. In these environments, obstacles similar to curbs are common and living spaces are small1,2. Efficiency and maneuverability are two key aspects of wheelchair performance in such settings1 .Validated skills tests for measuring wheelchair performance over obstacles and in tight spaces include timed exercises involving curbs and figure-eight patterns3. We hypothesized that some chairs designed for less-resourced settings would be easier than others for assistants to push in tight spaces and over curbs. College-aged participants (n=29) serving as assistants completed two three minute skills tests with two models of wheelchairs designed for less-resourced settings, the Motivation Rough Terrain and the Whirlwind RoughRider chair. The two skills tests consisted of three minute timed walk tests (TWT) with each chair on two short tracks, one encompassing a curb and the other in a figure eight around chairs. PolarPro heart rate monitors were used to collect heart rates. Distance traveled was measured and physiological cost index (PCI) was calculated. Subject feedback was obtained through visual analogue scale (VAS) questions and written comments for each exercise. Two-way within subject ANOVA analysis and post hoc paired t-tests were used to evaluate data. Within subject ANOVA indicated that the Motivation chair significantly outperformed the Whirlwind chair in PCI, TWT, and VAS responses. Post hoc paired t-tests of PCI values and VAS responses indicated that the differences between the Motivation and the Whirlwind were significant for both tracks. This data was normal and showed interaction but no crossover. The post hoc t-test analysis of TWT data, however, showed significant difference for the curb but only nearly significant difference for the figure-eight. In the written comments, subjects indicated a preference for the design of the Motivation chair mentioning certain features such as the single front castor wheel and the position of the handle bars. Our data indicates that the Motivation Rough Terrain chair may provide superior mobility to assistants serving people with disabilities in less-resourced settings specifically while maneuvering through tight spaces and over obstacles. Through this research, we hope wheelchair manufacturers will be encouraged to make improvements in wheelchair functionality for assistant pushers in less-resourced settings

A Comparative Study of the Energy Cost and Maneuverability for Pushers of Two Pediatric Wheelchairs Designed for Use in Low Income Countries

A comparative study of the energy cost and maneuverability for pushers of two pediatric wheelchairs designed for use in low income countries. Stormie Goodwin (undergraduate), Ruth Inwards (undergraduate), Karen Rispin LeTourneau University-Wheels Project Introduction Many wheelchairs are donated to developing countries without proper consideration of physical, cultural, and social needs1. Many children in wheelchairs around the world are unable to self-propel and are dependent on assistants to push their wheelchairs. Organizations designing wheelchairs for low-income countries are eager for outcomes research to inform design. We are performing a set of comparative tests on two pediatric wheelchairs designed for less-resourced settings, the Hope Haven KidsChair built in Guatemala, and a pediatric wheelchair built in Kenya by the Association of the Physically Disabled of Kenya (APDK). This is a partner study to a long term field study done in Kenya. Our results will give quantitative feedback to the manufacturers, with the goal of facilitating design improvements to the pediatric wheelchairs. Materials and methods In our study comparing the KidsChair and the APDK chair, volunteer college students completed six tasks: pushing each of the wheelchairs on rough and smooth ground, up and down a curb and ramp, on a track at a constant speed, and through a figure eight. The curb, ramp, and figure eight timed maneuverability test came from the Wheelchair Skills Test2. Fifty pounds of weight were placed on the chair to simulate the weight of a child. Physiological Cost Indices (PCI) and Time Walk Tests (TWT) were used to record the energy cost of pushing the wheelchairs. Additionally, each volunteer was asked to place a mark on a Visual Analogue Scale (VAS) questionnaire to give user input on the difficulty of each task. Preliminary Results Paired T tests of PCI, TWT and questionnaire data indicated the APDK chair outperformed the KidsChair on rough ground. Questionnaire data indicated the KidsChair outperformed the APDK chair on smooth ground. Subjects indicated it was significantly easier to push on smooth ground and up and down a ramp on the VAS questionnaire. Discussion Preliminary results seem to indicate that the APDK chair may be better suited for rough ground than the KidsChair. However, in the comment section of the VAS questionnaire, the APDK chair was repeatedly criticized for poor construction, suggesting that there may be need for improvement in manufacturing quality control. For the KidsChair, users mentioned front castors and stoppers caused difficulty maneuvering on rough ground. In May, we are planning to perform a parallel study at Joytown, a boarding school for children with disabilities in Kenya. References Fuhrer MJ. Am J Phys Med and Rehab. 80(7), 528-35, 1999. Kirby RL, Swuste J, Dupuis DJ, MacLeod DA, Monroe Mandi. 2002. The wheelchair skills test: a pilot study of a new outcome measure. Arch Phys Med Rehabil 2(83): 10-18

Cost of Rolling on Rough and Smooth Ground for Assistants Pushing the Motivation Rough Terrain and Whirlwind RoughRider Wheelchairs

In less-resourced settings, powered wheelchairs are rarely available for users who cannot self-propel[1]. These users must rely on somebody, usually family members or friends, for assistance to push them across variable terrain[2],[3]. In situations where people with disabilities are grouped together, assistants may themselves be disabled. Provision of mobility for the wheelchair user may be a great physiological cost for the assistant. Objective outcomes measures can provide valuable feedback to manufacturers which can constructively influence wheelchair design modification3,4. We hypothesized that measuring the energy cost for an assistant pushing two types of wheelchairs on rough and smooth ground would allow us to differentiate between the chairs and provide useful feedback to manufacturers. This study compared the Motivation Rough Terrain and Whirlwind RoughRider, wheelchairs designed for less-resourced settings. Able-bodied volunteer college-aged students (n=29: 16M, 13F, age 19±1.3) completed six-minute timed walk tests (TWT) with both wheelchair types on smooth and rough ground courses, the smooth course on a paved parking lot and the rough course on a gravel parking lot. Exercise and non-exercise heart rate was collected for each subject using Polar Pro monitors. Exercise heart rate consisted of the last four minutes of heart rate collected during the TWT. The physiological cost index (PCI) was then calculated4. Subjects completed a visual analog scale (VAS) question for each TWT. Two-way within-subject ANOVA and post-hoc paired t-tests were used to compare data. Results showed the Motivation Rough Terrain outperformed the Whirlwind RoughRider in most categories. ANOVA showed significant results with the Whirlwind chair having a higher PCI. Post-hoc paired t-tests showed a significantly higher PCI for the Whirlwind chair on both smooth and rough ground. There was no significance found between the two chairs for the TWT. VAS results indicated subjects perceived significantly greater difficulty with the Whirlwind chair than the Motivation chair on both smooth and rough ground. Comments revealed that subjects favored the single front castor of the Motivation chair. Based on the results of this study, it seems as though the design of the Motivation chair utilizes important features that could be of potential benefit to assistants pushing wheelchair users in less-resourced settings. These features may also have a positive impact on the production of efficient rough terrain wheelchairs

A Comparative Study on the Energy Cost of Pushing The Hope Haven KidChair and Free Wheelchair Mission Gen 2 Wheelchair

Introduction: Wheelchair skills tests can be used to assess the mobility provided by different types of wheelchairs [1]. A repeated measures study design in which participants complete skills in one type of wheelchair and then another minimizes individual variation [2]. Free Wheelchair Mission Generation 2 (FWM-2) and Hope Haven KidChair (H-KC) offer two pediatric-sized wheelchairs designed for use in low-resource settings. We hypothesize that four simple skills tests will be able to distinguish some strengths and weaknesses of the mobility provided by these two wheelchairs. Methods: This study was done in partnership with a host organization at a school for children with disabilities in a low-resourced setting. Study protocol was approved by ethics committees of all pertinent organizations. Wheelchair users who were identified by clinicians as safely able to use study wheelchair types and able to self-propel strongly on rough surfaces were invited to join the study. Participants completed consent and assent forms and were free to withdraw or to opt out of any aspect of the study. All skills tests were completed in one wheelchair type and then the other. The order of the tests and chairs were randomized and participants rested between tests. The following skills were included: rolling for 6 minutes on a rough ground track and 6 minutes on a smooth ground track; rolling for 3 minutes on a track in tight spaces; and timed transferring to the ground and back 3 times. We also collected participant feedback using a visual analogue scale question for each test. Results: Statistically significant differences indicated that participants performed better in the F-G2 than in the H-KC wheelchair in all skills tests except for the transfer test, which significantly favored the H-KC wheelchar. Discussion: The apparent poorer mobility provided by the H-KC may be due to its short wheelbase and anterior center of gravity, both of which are known to increase rolling resistance. These tests did not assess the appropriateness of the seating system. Wheelchair manufacturers have expressed that these findings are of interest to them and will impact future wheelchair design changes

Comparing Energy Cost and Maneuverability for Pushers of Two Pediatric Wheelchairs Designed for Low-income Countries

Summary: Our study compared two pediatric wheelchairs designed for less resourced settings, a wheelchair made by the Association of the Physically Disabled of Kenya and the Regency chair made in the US and distributed globally. The Regency chair outperformed the APDK chair in most aspects measured. Introduction: Many wheelchairs are donated to less-resourced countries by well-meaning organizations without regard to local, cultural, and physical conditions and without ensuring appropriate knowledge, tools, and support are present1. In the last ten years, several organizations have been manufacturing and distributing wheelchairs designed for low-income countries, however few outcomes studies have been done on these chairs. We completed a set of tests to compare two pediatric wheelchairs that are currently distributed in Kenya for children with disabilities. By providing accurate outcomes measures to manufacturers, we hope to enable design improvements2. Materials and Methods: During the 2010-2011 school year, local high school students pushed first graders sitting in the chairs on two surfaces (sidewalk and gravel drive) for six minutes. From heart rate data collected and distance covered, physiological cost indexes were calculated for pushing both chairs and time-walk test comparisons were made. In addition, a series of timed maneuverability tests from the Wheelchair Skills Test were performed, up and down a curb, up and down a ramp, and in a figure eight pattern3. Subject input was obtained by a visual analogue scale question and an opportunity to comment on each test. Results: Paired T tests showed that the APDK chair required significantly more energy to push than the Regency chair on both rough and smooth surfaces, and that the APDK chair was perceived as significantly harder to push on both terrains as well as more difficult to maneuver around tight spaces. Discussion: Results favored the Regency chair in all tests with significant differences. User comments indicated issues with the APDK chair about manufacturing quality control such as wobbling wheels due to lack of alignment and asymmetrically assembled frames. Results from this study as well as from a parallel study in Kenya have been provided to manufactures and on-going discussion is underway

Use of the Timed Walk Test, Physiological Cost Index and Prosthesis Evaluation Questionnaire As Outcomes Measurements for the Validation of the LEGS M1 Knee

LeTourneau Empowering Global Solutions (LEGS) administered a preliminary study comparing energy cost and patient satisfaction of three different prosthetic knee configurations. The LEGS M1 knee was compared with both a locked LEGS M1 knee and the OrthoEurope 4-bar (OE4bar) knee. Energy cost was measured using the Physiological Cost Index (PCI) and Timed Walk Test (TWT). Patient satisfaction was measured using the Prosthesis Evaluation Questionnaire (PEQ). The TWT and PCI indicated that the LEGS M1 knee was more costly to walk with than the OE4Bar conformation. In the comparison between the LEGS MI knee and the locked configuration, TWT and PCI indicated wide individual variation in energy cost, with some amputees walking consistently using less energy cost in the locked configuration while others walked with less energy cost using the LEGS M1 knee. The PEQ indicated amputee preference for the LEGS M1 knee over the locked conformation in all but two functional parameters, both pertaining to knee stability. Preliminary results indicate that these outcomes measures are collecting usable and pertinent data. Wide individual variation was found, possibly due to habituation issues. Follow-up data and a larger sample size are planned. Improvements to the protocol are ongoing, but overall these tests are robust and reliable for continued research

A conceptual framework to assess effectiveness in wheelchair provision

Background: Currently, inadequate wheelchair provision has forced many people with disabilities to be trapped in a cycle of poverty and deprivation, limiting their ability to access education, work and social facilities. This issue is in part because of the lack of collaboration among various stakeholders who need to work together to design, manufacture and deliver such assistive mobility devices. This in turn has led to inadequate evidence about intervention effectiveness, disability prevalence and subsequent costeffectiveness that would help facilitate appropriate provision and support for people with disabilities. Objectives: In this paper, we describe a novel conceptual framework that can be tested across the globe to study and evaluate the effectiveness of wheelchair provision. Method: The Comparative Effectiveness Research Subcommittee (CER-SC), consisting of the authors of this article, housed within the Evidence-Based Practice Working Group (EBP-WG) of the International Society of Wheelchair Professionals (ISWP), conducted a scoping review of scientific literature and standard practices used during wheelchair service provision. The literature review was followed by a series of discussion groups. Results: The three iterations of the conceptual framework are described in this manuscript. Conclusion: We believe that adoption of this conceptual framework could have broad applications in wheelchair provision globally to develop evidence-based practices. Such a perspective will help in the comparison of different strategies employed in wheelchair provision and further improve clinical guidelines. Further work is being conducted to test the efficacy of this conceptual framework to evaluate effectiveness of wheelchair service provision in various settings across the globe

Development of the Wheelchair Interface Questionnaire and initial face and content validity

Background: Because resources are limited in low- and middle-income countries (LMIC), the development of outcome measures is of interest. Wheelchair outcome measures are useful to support evidence-based practice in wheelchair provision. Objectives: The Wheelchair Interface Questionnaire (WIQ) is being developed to provide a professional perspective on the quality of the interface between a wheelchair and its user. This article discusses the development of the WIQ and its face and content validity. Method: During field studies in Kenya, we sought to include professional report data on the wheelchair–user interface that could be analysed to inform design changes. None of the existing measures was focused on the interface between users and their wheelchairs. The WIQ was developed to meet this need. To investigate face and content validity, 24 experienced wheelchair professionals participated in a study that included two rounds of an online survey and a focus group in Kenya. Results: Responses were categorised by topic and the WIQ was modified following each iteration. Participants affirmed the usefulness of a brief professional report measure to provide a snapshot of the user–wheelchair interface. Participants emphasised the importance of brevity, wide applicability and provision of specific feedback for wheelchair modification or design changes. The focus group agreed that the final version provided useful data and was applicable to virtually all wheelchair users in LMIC. Conclusion: These preliminary studies indicate initial face and content validity of the WIQ as a method for providing a professional perspective on the interface between a user and his or her wheelchair