The Impact of Functional Tasks: Analyzing Adults’ Sitting-Interface Pressures in Manual Wheelchairs

PURPOSE: Wheelchair users with spinal cord injuries, degenerative conditions, or congenital disabilities have an increased risk of developing pressure injuries (Stockton, Gebhardt, & Clark, 2009). To manage this risk, wheelchair users require effective strategies and equipment while performing occupations, including those at home. Occupational therapists assist in pressure care by assessing function and posture, prescribing and fitting equipment, and training clients and caregivers (Macens, Rose, & Mackenzie, 2011). Prior research has included isolated reaching and weight shifts while evaluating sitting interface pressure with pressure-mapping technology (Sonenblum, Vonk, Janssen, & Sprigle, 2014). However, occupational contexts are lacking in the methodologies of scholarly literature. Research is needed to determine how wheelchair users' sitting interface pressures are impacted by occupations and their associated reaching and weight shift patterns. This study's aim was to determine if differences in sitting interface pressures occur during functional tasks completed by adults sitting in manual wheelchairs. DESIGN: This quantitative study used a repeated measures design to evaluate differences of sitting interface pressures among four functional tasks completed by healthy adults who were at least 18 years old. Participants were recruited with convenience sampling. Researchers structured the tasks to ensure consistent performance in a home environment lab located on a university campus. Four tasks incorporated different reaching and weight-shift patterns: washing dishes, sweeping floor debris, retrieving a pan, and retrieving a water bottle from a refrigerator. Using an XSENSOR[R] pressure mapping system, researchers recorded participants' (n=48) peak pressures, overall average pressures, and times as they completed the tasks from a manual wheelchair. Two Silver Sport II wheelchairs accommodated different sizes of participants: an 18" x 16" manual wheelchair and a 22" x 18" Heavy Duty manual wheelchair. RESULTS: Nonparametric alternatives to a repeated measures ANOVA were used for statistical analyses. A Kruskal-Wallis test indicated no order effects. The Friedman's test indicated statistically significant differences for peak pressures among the task conditions, [chi square] (3) = 29.425, p < .0005. Overall average pressures were statistically significant, [chi square] (3) = 53.700, p < .0005. Time differences were also statistically significant for task c