The effects of whole body vibration exercise on metabolic systems in overweight Latino boys

With an increasing childhood obesity epidemic, efficient methods of exercise are sought to improve health. Vibration training has been in use for decades to improve strength and flexibility, however little is known about the metabolic effects from whole body vibration (WBV) exercise. We sought to determine if WBV exercise can improve insulin/glucose dynamics, lipid profile, body composition, leg strength and power in sedentary overweight Latino boys. Twenty overweight prepubertal Latino boys 8--10 years of age were randomly assigned to either a control (CON = 9, 9.1+/-0.9 yr, 57.8+/-18.5 kg) or 3 days per week WBV exercise (VIB = 11, 9.0+/-0.9 yr, 45.7+/-7.8 kg) for 10 weeks. Assessments were performed at baseline and 48 hours post last training session to avoid any confounding acute effects of exercise. Glucose/insulin indices were determined through an oral glucose tolerance test. Body composition was assessed using dual-energy x-ray absorptiometry. Physical performance was assessed using a Keiser leg press machine for strength and the Bassey Leg-extesion Rig for power. Comparisons of changes within and between groups for variables of interest were conducted using t tests and general linear model (p<0.05). Interestingly, there was a significant decrease in fasting glucose (p=0.04), triglycerides (p=0.02), and VLDL cholesterol (p=0.02), while leg press (p<0.05) and power (p<0.05) increased for the CON group. Significant increases in total lean mass (p<0.05), bone mineral density (p<0.05), leg press (p<0.05) and power (p<0.05) were observed for the VIB group when compared to baseline values. Between groups analyses revealed the CON group significantly lowered VLDL cholesterol (p=0.02) and triglycerides (p=0.02) compared to the WBV exercise group. The VIB group significantly increased total lean mass (p<0.01) compared to the CON group. These data suggest a controlled 10 wk WBV exercise program may not be effective for altering fasting insulin and glucose, insulin resistance, or lipids in prepubertal Latino boys. However a 10-week intervention may alter body composition in overweight boys primarily by increasing total lean mass.