Electrical Stimulation Alters FMD and Arterial Compliance in Extremely Inactive Legs

Abstract

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. 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). 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. Daily electrically induced training of an extremely deconditioned leg appears to enhance arterial compliance in the femoral artery and may normalize endothelial function.