Background. This study aimed to describe how people move about in manual wheelchairs (MWCs) during everyday life by evaluating bouts of mobility or continuous periods of movement.Methods. A convenience sample of 28 MWC users was recruited. Participants' everyday mobility was measured using a wheel-mounted accelerometer and seat occupancy switch for 1-2 weeks. Bouts of mobility were recorded and characterized.Results. Across 29,200 bouts, the median bout lasted 21 seconds and traveled 8.6 m at 0.43 m/s. 85% of recorded bouts lasted less than 1 minute and traveled less than 30 meters. Participants' daily wheelchair activity included 90 bouts and 1.6 km over 54 minutes. Average daily occupancy time was 11 hours during which participants wheeled 10 bouts/hour and spent 10% of their time wheeling. Spearman-Brown Prophecy analysis suggested that 7 days were sufficient to achieve a reliability of 0.8 for all bout variables.Conclusions. Short, slow bouts dominate wheelchair usage in a natural environment. Therefore, clinical evaluations and biomechanical research should reflect this by concentrating on initiating movement, maneuvering wheelchairs, and stopping. Bouts of mobility provide greater depth to our understanding of wheelchair use and are a more stable metric (day-to-day) than distance or time wheeled.

Abstract-The formation and underlying causes of p ressure ulcers (PUs) are quite complex, with multiple influencing factors. However, by definition pressure ulcers cannot form without loading, or pressure, on tissue. Clinical interventions typically target the magnitude and/or duration of loading. Pressure magnitude is managed by the selection of support surfaces and postural supports as well as body posture on supporting surfaces. Duration is addressed via turning and weight shifting frequency as well as with th e use of dynamic s urfaces that actively redistribute pressure on the body surfaces. This article shows that preventative interventions must be targeted to both magnitude and duration and addresses the rationale behind several common clinical interventions-some with more scientific evidence than others.

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OBJECTIVE To assess pressure ulcer (PU) risk in persons with mobility impairments using a large data set to identify demographic, laboratory, hemodynamic, and pharmacologic risk factors. METHODS The cohort of interest was persons with disabilities who have mobility impairments and are diagnostically at risk of PUs. To define this cohort, diagnoses that qualify patients for skin protection wheelchair cushions were used. Data were obtained from the Cerner Health Facts data warehouse. Two cohorts were defined: persons with and without a history of PUs. Analysis included descriptive statistics and multivariate logistic regression modeling. Variables retained in the model were identified using LASSO, gradient boosting, and Bayesian model averaging. MAIN RESULTS The resulting cohorts included more than 87,000 persons with a history of PUs and more than 1.1 million persons who did not have a PU. The data revealed seven disability groups with the greatest prevalence of PUs: those with Alzheimer disease, cerebral palsy, hemiplegia, multiple sclerosis, paraplegia/quadriplegia, Parkinson disease, and spina bifida. Ulcers in the pelvic region accounted for 82% of PUs. Persons with disabilities who were male or black had a greater prevalence of PUs. Physiologic risk factors included the presence of kidney or renal disease, decreased serum albumin, and increased serum C-reactive protein. CONCLUSIONS The results indicate that, although persons with disabilities can exhibit a wide functional range, they remain at risk of PUs and should be evaluated for proper preventive measures, including support surfaces and wheelchair cushions.

Given the limited pressure relief compliance, alternative approaches to pressure relief and improved training may be needed for some clients. Wheelchair design and prescriptions may also need to reflect participants' preferences for sitting in small and medium tilts and changing position frequently.