Neuromuscular and hormonal effects of a single session of whole body vibration

The purpose of this study was to compare the neuromuscular and hormonal responses following a single session of isometric half-squat exercise with and without the superimposition of whole body vibrations (WBV). Seven healthy males performed ten sets of one minute, with one minute rest between sets, of isometric exercise in half-squat position. This was conducted on two separate occasions, either with WBV (30 Hz; 3.5 g) or no vibration (Control). Maximal isometric unilateral knee extensions with doublet superimposed via percutaneous electrical stimulation were performed before and immediately following WBV and Control treatments. Significant decreases in maximal voluntary contraction were observed following both WBV and Control. Rate of torque development in the first 200 ms (RTD_200ms). salivary testosterone (T) and cortisol (C) concentrations, and voluntary activation were unaffected. However, RTD _200ms and T concentration tended to be lower following WBV only. The results of this study suggest that this acute WBV protocol does not greatly affect the neuroendocrine system, but does cause a low level of fatigue, most likely attributed to peripheral rather than central mechanisms.