Browsing by Subject "Wheelchairs"
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Item The influence of altering wheelchair propulsion technique on upper extremity demand(2010-08) Rankin, Jeffery Wade; Neptune, Richard R.; Barr, Ronald E.; Fernandez, Benito R.; Dingwell, Jonathan B.; Richter, William M.Most manual wheelchair users will experience upper extremity injury and pain during their lifetime, which can be partly attributed to the high load requirements, repetitive motions and extreme joint postures required during wheelchair propulsion. Recent efforts have attempted to determine how different propulsion techniques influence upper extremity demand using broad measures of demand (e.g., metabolic cost). However studies using more specific measures (e.g., muscle stress), have greater potential to determine how altering propulsion technique influences demand. The goal of this research was to use a musculoskeletal model with forward dynamics simulations of wheelchair propulsion to determine how altering propulsion technique influences muscle demand. Three studies were performed to achieve this goal. In the first study, a wheelchair propulsion simulation was used with a segment power analysis to identify muscle functional roles. The analysis showed that muscles contributed to either the push (i.e. delivering handrim power) or recovery (i.e. repositioning the hand) subtasks, with the transition period between the subtasks requiring high muscle co-contraction. The high co-contraction suggests that future studies focused on altering transition period biomechanics may have the greatest potential to reduce upper extremity demand. The second study investigated how changing the fraction effective force (i.e. the ratio of the tangential to total handrim force, FEF) influenced muscle demand. Simulations maximizing and minimizing FEF both had higher muscle work and stress relative to the nominal simulation. Therefore, the optimal FEF value appears to balance increasing FEF with minimizing upper extremity demand and care should be taken when using FEF to reduce demand. In the third study, simulations of biofeedback trials were used to determine the influence of cadence, push angle and peak handrim force on muscle demand. Although minimizing peak force had the lowest total muscle stress, individual stresses of many muscles were >20% and the simulation had the highest cadence, suggesting that this variable may not reduce demand. Instead minimizing cadence may be most effective, which had the lowest total muscle work and slowest cadence. These results have important implications for designing effective rehabilitation strategies that can reduce upper extremity injury and pain among manual wheelchair users.Item Wheelchair use in less resourced settings: a study on research quality, wheeled mobility in rural areas, and the user experience in the Lao People's Democratic Republic.(2015-08) Stanfill, Christopher John; Jensen, Jody L.; Cance, Jessica D.; Kohl III, Harold W.; Maslowsky, Julie; Lindsley, Robert B.The World Health Organization estimates that nearly twice as many people in the developing world are in need of wheelchairs compared to other mobility aids (e.g., prosthetics). Wheelchairs currently being manufactured in less resourced areas are rarely designed to withstand rural conditions with poor infrastructure, which leads to increased rates of product failure and/or abandonment. Global recognition of the need for more durable and efficient wheelchairs created a movement in evaluating how patients in these settings interact with various designs. This growing body of literature focuses primarily on the impact of wheelchair models in terms of performance and perception. Performance measures are often defined by physiological and biomechanical testing, while user perception outcomes are generated through feedback assessments, surveys, and interviews. Although the results from this literature suggests a preference toward tested wheelchairs compared to locally manufactured counterparts, it is necessary to expand on methodologies that can uncover further detail on product effectiveness. For example, wheeled mobility is a new effectiveness measure that has yet to be applied in less resourced settings. Additionally, it is important to continue implementing mixed methods study designs as these approaches yield the most comprehensive information about the relationship between performance and perception. In this series of studies, I expand upon the existing literature on wheelchair use in the developing world utilizing the mixed method approach and our purpose is threefold. The first study is an objective evaluation of previous work in the field that summarizes the brief history of this research and reveals the quality level of each respective piece of literature. In the second study, wheeled mobility is used to test the effect of different wheelchair designs that each feature different propulsion systems. Finally, the third study is an investigation of perceived quality of life among wheelchair users in rural areas of the Lao PDR with the use of semi-structured interviews. The combination of outcomes from these studies highlight the importance of mixed methods approaches when evaluating patients’ interactions with wheelchairs and assistive technologies as a whole. This research also serves as a reminder of the complexities associated with working in less resourced settings, but provides a framework of strategies that can guide improvements in global wheelchair service delivery.