Electrical Stimulation Alters FMD and Arterial Compliance in Extremely Inactive Legs

PURPOSE: The main aim of the study was to assess the effect and time course of 4 wk of electrically induced leg training on arterial compliance and endothelial function. METHODS: Six spinal cord-injured (SCI) individuals participated in 4 wk of daily one-leg functional electrical stimulation (FES) training for 30 min per session. Eight able-bodied individuals served as a control group (C) and were tested on one occasion. Echo Doppler measurements were performed before the FES training and after 1, 2, and 4 wk of training to measure vascular characteristics of femoral artery (FA), brachial artery (BA), and carotid artery (CA). RESULTS: Baseline arterial compliance of FA (SCI: 0.0185 +/- 0.063 mm2 x mm Hg(-1); C: 0.066 +/- 0.017 mm2 x mm Hg(-1), P = 0.001) and CA (SCI: 0.073 +/- 0.02 mm2 x mm Hg(-1); C: 0.102 +/- 0.02 mm2 x mm Hg(-1), P = 0.02) was significantly decreased in SCI. Baseline endothelial function in the leg was significantly enhanced in SCI compared with C (SCI: 11 +/- 1.3%; C: 7.9 +/- 0.9%, P = 0.001). No differences between the groups were found for arterial compliance and endothelial function in the arm. Vascular changes after FES training showed an increase in arterial compliance (significant at week 4, P < 0.05) and a decrease in FMD response (significant at weeks 2 and 4, P < 0.05) in the FA of the trained leg only, with no changes evident in the other arteries examined. CONCLUSION: Daily electrically induced training of an extremely deconditioned leg appears to enhance arterial compliance in the femoral artery and may normalize endothelial function.