A total of 20 participants with spinal cord injury will be recruited. Subjects will undergo study procedures including: AP and Control protocols. Skin blood flow and interface pressure will be collected non-invasively (from outside the body) during both protocols. During AP protocols, subject will be asked to lie on side (10 min), on back on AP overlay (40 min), on side (30 min), on back on OR overlay (40 min), and on side (10 min). During Control protocol, subject will be asked to lie on side (10 min), on back on OR overlay (40 min), and on side (10 min). Subject will then proceed to vascular control measures, including: non-invasive skin blood flow and tissue oxygen measurements with mild heating and electrical stimulation. Findings from this study will help us understand the effectiveness of the AP overlay on skin blood flow response during prolonged lying in bed.