Neuromuscular and Hormonal Effects of a Single Session of Whole Body Vibration Exercise

Abstract

Vibration exercise has been reported to stimulate musculo-skeletal structures and may represent an effective non-pharmacologic therapeutic intervention to target several physiological systems in a similar manner to resistance training. PURPOSE: To evaluate the neuromuscular and hormonal responses to an acute bout of isometric half-squat exercise with and without the superimposition of whole body vibrations (WBV). METHODS: Seven healthy males (22.3±2.7 yrs) performed ten sets of one minute with one minute rest between sets, of isometric exercise in half squat position. Two separate trials were conducted either with WBV (30 Hz; 3.5 g [1g= 9.81m-s2]) or no vibration (Control). Salivary concentration of Testosterone (T) and Cortisol (C) and maximal isometric unilateral knee extensions (MVC) with doublet superimposed via percutaneous electrical stimulation were completed before, immediately after, 1h, 2h and 24h after treatment. RESULTS: Significant decreases in MVC were observed immediately after (229.4±53.2Nm), 1h (231.6±59.9 Nm), and 2h (233.0±59.1 Nm) after WBV compared to baseline (252.7±56.4 Nm; P < 0.05). No significant change was identified in Control. Rate of torque development in the first 200 ms (RTD200ms), voluntary muscle activation, and salivary T and C concentrations were unaffected in both conditions. However, there was a trend for change over time in C (P = 0.052), with an increase after WBV and a decrease after Control. CONCLUSION: A 10min session of WBV was shown to produce an acute reduction in MVC in healthy individuals, which recovered after 24h. No significant changes were identified in salivary T and C suggesting that WBV with low acceleration does not represent a stressful stimulation for the neuroendocrine system.