Seat-interface pressure: A pilot study of the relationship to gender, body mass index, and seating position

Objectives: To investigate the relationship between interface pressure and gender, body mass index (BMI), and seating positions, and to evaluate the implications for clinical practice. Design: Group design. Setting: Pressure mapping laboratory. Participants: Sixty-three student volunteers (44 women, 19 men; mean age, 22.2+/-5.1y). Interventions: Seated-interface pressure was measured using the Force Sensing Array pressure mapping system. Seating positions used included recline (10degrees, 20degrees, 30degrees), foot support, and foot elevation. Main Outcome Measures: Interface pressure in the form of both average pressure (mean of the pressure sensor values) and maximum pressure (highest individual sensor value). Results: Both average and maximum pressures were independent of gender, while average pressure had a significant positive correlation with BMI (r=.381, alpha=.01 level). Recline of the chair by 30degrees significantly reduced average pressure (P<.001), whereas recline by 10&DEG; or 20&DEG; had no significant effect. Recline by 10&DEG;, 20&DEG;, and 30&DEG; did not significantly alter maximum pressure. Elevation of the feet on a footstool reduced average pressure to a level approaching statistical significance, while supporting participants' feet versus leaving them unsupported significantly increased average pressure at a 0&DEG;, 10&DEG;, 20&DEG;, and 30&DEG; recline (P<.01) and maximum pressure at 0degrees, 10degrees (P<.01), and 30&DEG; (P<.05). Conclusions: Elevating clients' feet and reclining their chair by 30degrees reduced interface pressure and the associated risk of pressure ulcer development. Additional research is required, however, to replicate this study with participants at increased risk of pressure ulcer development.