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A high prevalence of manual wheelchair rear-wheel misalignment could be leading to increased risk of repetitive strain injuries

OTT, Joseph
HENDERSON, Travis
WILSON-JENE, Holly
KOONTZ, Alicia
PEARLMAN, Jonathan
2021

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Purpose: To determine the prevalence and severity of manual wheelchair rear wheel misalignment in community-dwelling manual wheelchair users and estimate the associated increases in rolling resistance (RR) and risk of repetitive strain injuries (RSIs).


Materials and Methods: Data were collected in an outpatient rehabilitation clinic, a university research laboratory, and at adaptive sporting events in the United States. Two hundred active, self-propelling man- ual wheelchair users were recruited. Angular misalignment (referred to as toe angle) while the wheelchair was loaded with the user, and the difference between the maximum and minimum toe angle (referred to as slop) with the wheelchair unloaded.

 

Results: Average results for toe angle and slop (movement in the rear wheels) were 0.92 and 0.61 degrees, respectively. Using a lab-based testing method, we quantified the impact of increased RR forces due to misalignment in increased RR forces. Our results indicate that the average toe angle while under load and slop, without loading, measured in the community increase required propulsion force by 3.0 N. Combined toe angle and slop (i.e., the worst-case scenario) added increased propulsion force by 3.9 N. Conclusions: We found that rear-wheel misalignment was prevalent and severe enough that it may increase the risk for RSIs and decrease participation. To mitigate this issue, future work should focus on reducing misalignment through improved maintenance interventions and increased manufacturing qual- ity through more stringent standards.

The influence of a contoured seating base on pressure distribution and discomfort

DE MARE, Lieke
DE GROOT, Bas
DE KONING, Fleur
GEERS, Richard
TETTEROO, Daniel
2021

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Purpose: This research paper examines how contouring of a wheelchair seating base can help prevent pressure sores by distributing pressure over the buttocks. Contouring wheelchair cushioning is already done to some extent and has proved to be beneficial for pressure distribution. We researched the effect of contouring the seating base, and whether contouring the seating base affects effectiveness in pressure distribution and perceived discomfort.

 

Materials & methods: 13 healthy participants performed a within-subject experiment with three differ- ently contoured seating bases. Perceived comfort and seating pressure were measured for each condition.
Results: Results indicate that a more contoured base is positive for both comfort and increased pressure distribution.

 

Conclusions: Contoured seating bases can provide increased comfort and improved pressure distribution over flat seating bases. Future research should examine the effect of contouring on stability, as well as compare the effects of contoured seating bases and contoured cushions.

Design journey of an affordable manual standing wheelchair

SHAIKH-MOHAMMED, Javeed
DASH, Swostik Sourav
SARDA, Vivek
SUJATHA, S
2021

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Purpose: Only 1 in 10 people with disabilities can access assistive devices, underlining the critical need for low-cost assistive products. This paper describes the design evolution of a manual user-operated standing wheelchair (SWC), translating from prototype to product.


Methods: The SWC design has been refined over 5 years through multiple iterations based on comments from user trials. The SWC product, Arise, provides standing functionality, facile outdoor mobility, afford- ability, customisability, and is aesthetically pleasing. A one-time fitting and training ensure optimal effort for operation, correct posture, and comfortable user experience. The SWC accommodates users of differ- ent sizes and body weights (up to 110kg) and minimises user effort with the use of a gas spring. Incorporating discrete adjustments enables customisation while retaining the advantages of mass manu- facturing, which is necessary for ensuring affordability.

 

Results: The SWC has been field-tested and well received by over 100 wheelchair users, and Arise was launched recently by the industry partner.


Conclusions: It should be noted that RESNA cautions on the use of any standing device without medical consultation. Nevertheless, with appropriate dissemination and awareness, it is anticipated that the afford- able SWC product, Arise, will immensely benefit the eligible users and make a difference in their quality of life.

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