Optimizing wheelchair cushion design through pressure mapping analysis for pressure ulcer risk reduction

Individuals with limited mobility who rely on wheelchairs often experience localized high-pressure areas during prolonged sitting, which reduces seating comfort and affects load distribution. Previous studies have employed contoured seat cushions to reduce localized high-pressure areas by increasing the contact area, thereby lowering peak contact pressures. Existing contoured cushions primarily depend on the mechanical properties and quality of the cushioning material, which can limit their effectiveness in maintaining consistent pressure redistribution. This study designed a standardized contoured seat cushion that consists of an outer shell shaped to support the buttocks, consisting of an outer shell made of thermoplastic to support the buttocks, coated with seven types of cushioning materials commonly used for seating applications and widely available on the market: high-density PU foam, perforated and non-perforated latex, rebounded foam, EVA foam, and memory foam. The cushions were integrated into wheelchair units, and pressure distribution was measured using a pressure matrix sensor. The study included 31 male subjects with body weights, heights, and ages representing the average adult Indonesian male population. Peak pressures for all types of cushioning layers were measured in the range of 1.31–2.69 kPa. In contrast, when the contoured thermoplastic shell was not used, all foam layers produced peak pressures above 3 kPa, and even over the safe pressure limit, increasing the likelihood of pressure ulcer development. The results indicate that the optimized contour design and material selection effectively redistribute pressure and reduce peak contact stress.