Measurement of interface (or contact) pressure is important in assessing tissue viability in relation to pressure sore prevention and may be achieved through pressure mapping techniques. This article reports on two pilot studies using the Force Sensing Array pressure mapping system in a laboratory setting. The purpose of Study 1 was to examine the consistency of readings from the system across 1-min trials of repositioning, and Study 2 aimed to investigate changes in interface readings over a 20-min sitting period. Analyses on measurements of average pressure (mean of all sensor values) and maximum pressure (highest individual sensor value) were performed using the t test and repeated-measures analysis of variance. The results demonstrated that the use of average and maximum pressure measurements reflected only low reliability and that 6 min was likely to be the optimal sitting time required before stable pressure measurement. However, because of the limitations of using small convenience samples of healthy participants (n = 44 for Study 1, n = 20 for Study 2), these studies should be replicated with larger samples of healthy participants and then verified with disabled populations before adoption into clinical practice.