Arterial dysfunction contributes to the development of cardiovascular disease (CVD), which is currently afflicting millions of individuals. The use of the amino acid L-citrulline has been suggested as a potential aid for the treatment of CVD by increasing endothelial production of Nitric Oxide (NO). Whole body vibration (WBV) is new and effective form of exercise that is feasible for clinical populations and has been proven to decrease blood pressure (BP) and arterial stiffness and increase muscle mass and strength. Therefore, the purpose of this study was to investigate if the combination of WBV training (WBVT) plus L-citrulline supplementation would induce positive additive effects and would be an effective means to ameliorate arterial stiffness, endothelial function, BP and muscle strength/mass in postmenopausal women.
The purpose of this study is to investigate the effects of 8 weeks combination of WBVT plus L-citrulline supplementation on arterial stiffness, endothelial function, BP and muscle strength/mass in overweight/obese postmenopausal women. The specific aims of the study are: 1. To investigate if the additive effect of 8 weeks of WBVT combined with L-citrulline supplementation are more efficacious than either treatment alone in ameliorating cardiovascular disease risk factors by assessing arterial stiffness (aortic, systemic, and leg), aortic BP and wave reflection, and autonomic function (heart rate variability, vascular sympathetic activity \[low-frequency power of systolic BP variability\], and baroreflex sensitivity). Flow mediated dilation and circulating levels of adipocytokines (adiponectin and leptin) and endothelial-derived vasodilators (NO metabolites \[NOx\], 6-keto PGFIa, insulin, and ghrelin) and vasoconstrictors (endothelin-1 \[ET-1\],8-iso PGF2a,vascular endothelium growth factor \[VGEF\]) will be assessed as secondary outcome variables. 2. To evaluate the extent to which 8 weeks of WBVT combined with L-citrulline improves body composition assessed by changes in fat mass and lean mass using dual-energy x-ray absorptiometry and waist circumference. 3. To determine the additive effect of 8 weeks of WBVT combined with L-citrulline supplementation on muscle strength. These will be evaluated using the eight-repetition maximum test for the leg press and chest press exercises
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
DOUBLE
Enrollment
60
The Whole body vibration training intervention consists of lower-body exercise in a vibration platform 3 times per wk for 8 wk. The subjects will perform static and dynamic exercises for the legs on the vibration platform. Dynamic exercises will be performed with slow controlled movements starting from an upright position into a 60 degree knee flexion (squat) and maximal heel elevation (toestand). Static exercises will be performed without movement in the joint angles described previously. The training volume will increase progressively over the 12-week training period by increasing the intensity of vibration, duration of the exercise set (30-60 sec), number of sets per exercise, and total duration of the training session, and decreasing the duration of rest periods (30-60 sec).The intensity of vibration and amplitude will also be increased progressively (25-30 Hz of frequency and from low to high amplitude).
FSU College of Human Sciences
Tallahassee, Florida, United States
Blood Pressure
Non-invasive measures of brachial and aortic blood pressure
Time frame: 8 weeks
Arterial Stiffness and pressure wave reflection
Using pulse wave velocity of the aorta, systemic, and legs and the augmentation index from radial tonometry
Time frame: 8 weeks
Endothelial and autonomic functions
By measuring circulating levels of adipocytokines (adiponectin and leptin) and endothelial-derived vasodilators (NOx, 6-keto PGFIa, insulin, and ghrelin)and vasoconstrictors (ET-1 and 8-iso PGF2a, VEGF).In addition, heart rate variability, vascular sympathetic activity \[low-frequency power of systolic BP variability\], and spontaneous baroreflex sensitivity will be assessed from electrocardiogram and beat-by-beat digital blood pressure.
Time frame: 8 weeks
Body Composition
By measuring fat mass and lean soft tissue mass from dual-energy x-ray absorptiometry and waist circumference
Time frame: 8 weeks
Muscle Strength
Using eight-repetition maximum (8-RM) test for the leg press and chest press exercises
Time frame: 8 weeks
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