Di Giminiani R et al, PLoS ONE 9(11): e111521
Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila Italy
Thirty male students were randomly assigned to a high vibration group (HVG), a low vibration group (LVG), or a control group (CG) in a randomized double-blind, controlled-parallel study design
The HVG and LVG participants were exposed to a series of 20 trials 10-s of synchronous whole-body vibration (WBV) with a 10-s pause between each trial and a 4-min pause after the first 10 trials
Outcome measures were growth hormone (GH), testosterone, maximal voluntary isometric contraction during bench-press, maximal voluntary isometric contraction (MVC) during handgrip, and electromyography root-mean-square (EMGrms) muscle activity (pectoralis major [PM], triceps brachii [TB], anterior deltoid [DE], and flexor carpi radialis [FCR])
The GH increased significantly over time only in the HVG (P = 0.003)
Testosterone levels changed significantly over time in the LVG (P = 0.011) and the HVG (P = 0.001)
MVC during bench press decreased significantly in the LVG (P = 0.001) and the HVG (P = 0.002)
In the HVG, the EMGrms decreased significantly in the TB (P = 0.006) muscle. In the LVG, the EMGrms decreased significantly in the DE (P = 0.009) and FCR (P = 0.006) muscles
Synchronous WBV acutely increased GH and testosterone serum concentrations and decreased the MVC and their respective maximal EMGrms