The influence of cuff location on the oxygenation and reperfusion of the foot during ischemic preconditioning: A reliability study

Ischemic preconditioning (IPC) involves the application of occlusion cycles, typically prior to exercise. IPC is commonly applied at the arm or thigh for improving exercise performance, which can be combined with near-infrared spectroscopy (NIRS) to assess the microcirculation and tissue oxygenation. Despite the use of NIRS during IPC, few studies have investigated the reliability of NIRS during lower limb IPC with no relevant publications investigating IPC at the ankle. Therefore, the purpose of this study was to investigate the intra-session reliability in the NIRS measurements during repeated IPC at the thigh, ankle and arm. Eighteen participants volunteered. IPC was applied at the thigh (220 mmHg), ankle (individualized arterial occlusion pressure: 212 ± 24 mmHg) and arm (220 mmHg) in a randomized order involving 3 repeated cycles of 5-min occlusion and reperfusion, within a session. NIRS recorded tissue oxygen saturation (SO₂), oxygenated (O₂Hb) and deoxygenated hemoglobin (HHb) at the abductor hallucis muscle. Reliability was assessed using intraclass correlation coefficients. For all NIRS measurements assessed, there was excellent reliability (All ICC > 0.94) for the average, minimum and maximum values. The results indicate that IPC can successfully be applied at the ankle, offering reliable measures between three repeated occlusions within a session.