Pressure ulcer prevention has long focused on the reduction of the magnitude and duration of skin and soft tissue loading. Recently, a new pressure-redistributing (PR) patient support surface modality has emerged that combines foam and air cells. These hybrid mattresses can be used in static (or reactive) mode to increase envelopment and immersion of patients sleeping on these surfaces, or they can be connected to a pump unit to sequentially inflate and deflate the air cells so providing an active support surface (alternating pressure). This study compared the contact pressures applied while ten healthy volunteers rested upon a powered hybrid PR mattress, a non-powered hybrid mattress and a foam mattress. Accordingly, the highest pressure recorded at the sacrum and buttocks was used to compare these static surfaces with the powered hybrid mattress. No statistically significant differences were found between the coefficient of variation across the five support surface configurations suggesting that each surface provided similar levels of envelopment (F=2.18, p=0.086). The minimum contact pressure applied by the powered hybrid mattress was lower than the pressures applied to the sacrum by the foam mattress (p=0.015), the powered hybrid in static mode (p=0.009) and the maximum pressures applied by the powered hybrid mattress (p=0.000). Body contact area was higher upon the non-powered hybrid mattress than the powered hybrid in static mode (p=0.003) and the powered hybrid when the lowest contact pressures at the sacrum were observed (p=0.052). No other differences between the tested mattresses achieved statistical significance.