Hormonal and Neuromuscular Responses to Mechanical Vibration Applied to Upper Extremity Muscles

Abstract

ObjectiveTo investigate the acute residual hormonal and neuromuscular responses exhibited following a single session of mechanical vibration applied to the upper extremities among different acceleration loads.MethodsThirty male students were randomly assigned to a high vibration group (HVG), a low vibration group (LVG), or a control group (CG). A randomized double-blind, controlled-parallel study design was employed. The measurements and interventions were performed at the Laboratory of Biomechanics of the University of L'Aquila. 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. The CG participants assumed an isometric push-up position without WBV. The outcome measures were growth hormone (GH), testosterone, maximal voluntary isometric contraction during bench-press, maximal voluntary isometric contraction during handgrip, and electromyography root-mean-square (EMGrms) muscle activity (pectoralis major [PM], triceps brachii [TB], anterior deltoid [DE], and flexor carpi radialis [FCR]).ResultsThe GH increased significantly over time only in the HVG (P = 0.003). Additionally, the 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.ConclusionSynchronous WBV acutely increased GH and testosterone serum concentrations and decreased the MVC and their respective maximal EMGrms activities, which indicated a possible central fatigue effect. Interestingly, only the GH response was dependent on the acceleration with respect to the subjects' responsiveness.

Effects of Whole Body Vibration Intervention on Handgrip Strength of Brazilian Healthy Soldiers

“…In contrast, Giminiani et al (2014) showed no significant difference on handgrip strength. Thirty male students were randomly assigned to a high vibration group (HVG), a low vibration group (LVG), or a control group (CG) and were exposed to a series of 20 trials 10 s of synchronous WBV with a 10-s pause between each trial and a 4-min pause after the first 10 trials.…”

“…Studies have also described important effects of vibration exposure on upper body muscular activity, as an increase in skeletal muscle activity in the arms (Marín et al, 2015;Marín et al, 2011;Marín et al, 2013) and on the handgrip strength (Giminiani et al, 2014;Kurt et al, 2015) .…”

Alterations on the plasma concentration of hormonal and non hormonal biomarkers in human beings submitted to whole body vibration exercises

“…It exerts biological effects throughout a man's entire life (Ohl and Quallich, 2006). Concerning the effect of the WBV exercise in the plasma level of testosterone, Bosco et al, 2000;Santos-Filho et al, 2011;Nanemi, 2012 andDi Giminiani et al, 2014 have reported significant increase in testosterone levels in response to these exercises. However, other authors have not found increase in the concentration of testosterone due to WBV exposure (Cardinale et al, 2006;Erskine et al, 2007).…”

Biological Effects of Paullinia cupana (Guarana) in Combination with Whole-Body Vibration Exercise in Wistar Rats

“…In addition, WBV exercises have been considered as a noninvasive and non-pharmacological intervention [19]. The effects of WBV exercises on plasma concentrations of selected biomarkers have been studied in human beings [20][21][22]. In addition, some investigations have reported that WBV exercises could improve muscle activity, force and power [23,24], balance and flexibility [25], and cognitive performance [26].…”